Driving technique for activating liquid crystal device

ABSTRACT

To provide a high-response and wide-viewing-angle liquid crystal panel capable of causing a transition of liquid crystal, which is called the OCB mode, into a bend configuration in a short time, there is provided a period in which a potential difference higher than that in a normal image display period is continuously applied between gate lines and opposing electrodes or between pixel electrodes and the opposing electrodes of the liquid crystal panel.  
     Also, ingenuities are exercised on the period in which the potential difference is continuously applied between them and on the structure of picture elements.

TECHNICAL FIELD

[0001] The present invention relates to a liquid crystal device and,more particularly, to an activating technique for driving liquid crystaldevice in which a liquid crystal layer takes a splay configuration whenno voltage is applied and takes a bend configuration when it fulfillsits function such as a display.

BACKGROUND ART

[0002] 1. General Background Art

[0003] Liquid crystal device takes the holding mode in which whenbrightened or darkened, each picture element is held in its brightenedstate or in its darkened state in each display period by electricoperation of liquid crystal element. Accordingly, the liquid crystaldevice produces a static image of little flickering, as compared with acathode ray tube that is brightened only for a further shortened time ineach display period, which is one of the characteristic features of theliquid crystal device.

[0004] In recent years, with increased speed and capacities of CPU andmemory, personal computers have come to be able to perform the movingimage processing with ease. Under these circumstances, improvement inimage quality of the moving image displayed in the liquid crystaldisplay device is now being desired.

[0005] The screen of a TV receiver as a broadcasting receiver isbecoming bigger. In the cathode ray tube, with an enlarged area of thescreen, the depth thereof increases to a degree, in terms of which thecathode ray tube is not desirable for the demand for a thin-profile TV.The liquid crystal display device is being thought of as an answer tothe demand.

[0006] The current TN aligned liquid crystal device that is a mainstreamof the liquid crystal device is slow in response time. Also, in contrastto the cathode ray tube in which each picture element emitsinstantaneously for a very short time in each display period, the liquidcrystal device takes the holding mode in which for example when theliquid crystal device is in the ON mode (opens and emits), each pictureelement is kept on emitting light in each display period. This can causedistortion of the moving image produced, such as appearing to leavetraces when a moving image is displayed. Thus, the liquid crystal deviceis inferior to the cathode ray tube in image quality.

[0007] The liquid crystal having the bend configuration, which is calledthe OCB mode (type) as disclosed, for example, by Japanese Laid-open(unexamined) Patent Publication No. Sho 61-116329 or No. Hei 7-84254,contributes to the solving this problem. The OCB mode can satisfactorilymeet the demands for the moving image to be displayed at a high-speedresponse and at a wide viewing angle and the demands for the enlargementof screen, to provide a big screen display with thin-profile and lowpower consumption, as compared with the cathode ray tube.

[0008] The devices using the liquid crystals have begun to be applied todisplays for liquid crystal plasma displays, circuits and devices usinglight logic devices, as well as to displays for word processors,personal computers and receivers of TVs. For these applications as well,the OCB mode of liquid crystal has been marked, from the viewpoints ofgood display performance and high-speed response.

[0009] 2. Background Art as Viewed from the Aspect of the Problem to beSolved by the Invention

[0010] However, in this mode of liquid crystal, the transition of theliquid crystals from the splay configuration 51 as shown in FIG. 1 (1)and (2) to the bend configuration as shown in FIG. 1 (3) requires tokeep on applying a high potential difference to a liquid crystal layerfor a specified time or more. The application of such a high voltage tothe liquid crystal layer, however, imposes burden on transistor elementsand wirings and leads to cost increase. The technique of enabling thetransition of the liquid crystals into the bend configuration in an easyand reliable manner through the application of a possible voltage andcurrent to the elements and wirings that are now in wide use has not yetsuccessively been realized. As a result of this, this mode of the liquidcrystal has not yet gone far enough to be universally used at thisstate.

[0011] Thus, in the OCB mode of liquid crystal device or driving circuitthereof, development of the low-cost technique is now being desired ofenabling the transition of the liquid crystal layer into the bendconfiguration in a reliable manner in a short time without imposing anyburden on the currently presented hardware, such as transistor elementsand wirings.

[0012] Likewise, the technique of activating the liquid crystal devicereliably and easily even when applied for another intended applicationsis now being desired.

DISCLOSURE OF THE INVENTION

[0013] The present invention has been made with the aim of solving theabove-mentioned problems. According to the present invention,ingenuities are exercised on the structure of each element of the deviceusing the liquid crystals. Likewise, ingenuities are exercised on theway of applying a highest possible voltage for the activation and on thetiming when the voltage is applied. To be more specific, ingenuities areexercised on the following.

[0014] According to the invention of the first inventive group,ingenuities are exercised on the structure of the liquid crystal displaydevice of the OCB mode and the like. As a result of this, electric fieldintensity higher than that in a normal (plain) image display period isapplied to a liquid crystal layer between gate lines on a firstsubstrate and an opposing electrode on the second substrate at a startupto thereby produce a transition of that part of the liquid crystal layerinto the bend configuration. With this as a nucleus (seed), thetransition grows and extends over the whole area of the liquid crystallayer, which is an intended aim of the invention. In this case, sincethe gate lines that are driven at high voltage as compared with theother parts in the liquid crystal panel are used, high field intensitycan be applied to the liquid crystal layer without imposing burden onsource line driven IC and pixel transistors.

[0015] In order to apply higher field intensity to the liquid crystallayer, an insulating layer on the gate line is reduced in thickness toincrease the capacity of the insulating layer, so that a ratio ofpartial pressure between the gate line and the opposing electrode isvaried.

[0016] Likewise, the insulating layer on the gate line is formed ofmaterial of high specific inductive capacity to increase the capacity ofthe insulating layer, so that a ratio of partial pressure between theliquid crystal layer between the opposing electrode and the insulatinglayer is varied.

[0017] Likewise, a gate line forming metal is increased in thickness ata portion where no other metal layer or no semiconductor layer ispresent between the gate line and the liquid crystal layer, whereby theliquid crystal layer on the gate line is reduced in thickness by theorder of 0.5-1.5 μm.

[0018] Likewise, the source line forming metal is laminated on the gateline in electric contact therewith at a portion where no other metallayer or no semiconductor layer is present between the gate line and theliquid crystal layer, whereby the thickness of the gate line isincreased and thereby the thickness of the liquid crystal layer on thegate line is reduced.

[0019] Likewise, the source line forming metal is laminated on the gateline not in electric contact therewith at a portion where no other metallayer or no semiconductor layer is present between the gate line and theliquid crystal layer, whereby the thickness of the liquid crystal layeron the gate line is reduced.

[0020] Likewise, the opposing electrode on the second substrate isdivided into a part confronting the gate line on the first substrate andthe remaining part, and a higher voltage is applied to the opposingelectrode at the part confronting the gate line than at the remainingpart.

[0021] Likewise, a color filter forming resin is laminated on the secondsubstrate at a portion confronting the gate line on the first substrate,to reduce the thickness of the liquid crystal layer on the gate line.

[0022] Likewise, a pillar-shaped spacer is formed on the secondsubstrate at a portion confronting the gate line on the first substrate,so that the opposing electrode is formed between the pillar-shapedspacer and the liquid crystal layer, to reduce the thickness of theliquid crystal layer on the gate line.

[0023] According to the second inventive group, ingenuities areexercised on the activating circuits and the like of the liquid crystaldevice, such that potential difference higher than that in the normalimage display period is continuously applied between the pixel electrodeof the first substrate and the opposing electrode of the secondsubstrate in accordance with prescribed orders and rules.

[0024] This can make variation of the opposing electrodes available. Thetransition to the bending alignment is accelerated by the change in scantiming and potential difference applied and the control of the change.

[0025] Likewise, there is provided a period in which a primary potentialdifference different from that in the normal image display period iscontinuously applied between pixel electrode of the first substrate andthe opposing electrode of the second substrate, whereby the potentialdifference is increased to be applied to a broadest possible area of theliquid crystal layer. This produces increased nuclei for the transitionto the bend configuration to accelerate enlargement of the bend region,so that the transition into the bend configuration is performed in ashort time.

[0026] Likewise, in the driving mode in which a primary potentialdifference application step of applying a primary potential difference,different from that in the normal image display period, between thepixel electrode on the first substrate and the opposing electrode on thesecond substrate; a secondary potential difference application step forapplying a secondary potential difference smaller than the primarypotential difference are alternately controlled at least once for eachstep in a repeat control step, the time range of from 50% to 95% of eachrepeated period of the application is controlled in the primarypotential difference application step, and the primary potentialdifference application step of producing the nuclei for the bendconfiguration and enlarging the bend region and the secondary potentialdifference application step of re-arranging the liquid crystal layer ina part thereof where no nucleus for the bend configuration was producedor no enlargement of the bend region was provided are alternatelyperformed, whereby the transition to the bend configuration isaccelerated over the whole area of the panel.

[0027] Likewise, there is provided a charging sub-step of applying tosource lines a potential in which a pixel electrode potential variationis reflected in the opposing electrode potential, the pixel electrodepotential variation being induced by the potential variation of the gatelines when the pixel transistor is switched to OFF from ON in thesecondary potential difference application step, to charge the pixelelectrodes.

[0028] Also, in the primary potential difference application step, thepotential of the source line is modulated to a potential different fromthat in the secondary potential application step so that the primarypotential difference can be increased. Thus, the production of thenuclei for the bend configuration and the enlargement of the bend regionare further accelerated, so that the transition to the bendconfiguration is accelerated over the whole area of the panel.

[0029] Likewise, the period in which the drive for causing thetransition of the liquid crystal layer to the bend configuration isinitiated from the secondary potential difference so that the liquidcrystal layer can be re-arranged, first. This provides the result thatin the primary potential difference application step of applying theprimary potential difference between the pixel electrode and theopposing electrode, the production of the nuclei for the bendconfiguration and the enlargement of the bend region are furtheraccelerated, so that the transition to the bend configuration isaccelerated over the whole area of the panel.

[0030] Likewise, in the driving mode in which the primary potentialdifference application step of applying the primary potential differencebetween the pixel electrode and the opposing electrode and the secondarypotential difference application step of modulating the potentialdifference between the pixel electrode and the opposing electrode to thesecondary potential difference smaller than the primary potentialdifference are alternately provided at one time for each to cause thetransition of the liquid crystal layer to the bend configuration, imageinformation large in potential difference applied to the liquid crystallayer is displayed at least one field during a period from aftercompletion of the primary difference application step or the secondarypotential difference application step until the shift to the normalimage information display period, whereby the transition to the bendconfiguration is accelerated over the whole area of the panel.

[0031] The third inventive group is intended for stabilization of theliquid crystal layer at a startup. Accordingly, ingenuities areexercised on the way of turning the power on and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

[0032]FIG. 1 shows diagrams illustrating the condition of splayconfigurations (1) and (2) of liquid crystal elements and the conditionof bend configuration (3);

[0033]FIG. 2 shows a plan view and a sectional view of a principal partof the structure for a single picture element of a conventional liquidcrystal panel;

[0034]FIG. 3 is a schematically illustrated diagram of capacitive loadbetween a gate line electrode and an opposing electrode in aconventional liquid crystal panel and in some embodiments;

[0035]FIG. 4 shows diagrams of a constitution for one picture element ofthe liquid crystal panel of Embodiment 1-1;

[0036]FIG. 5 shows diagrams of a constitution for one picture element ofthe liquid crystal panel of Embodiment 1-2;

[0037]FIG. 6 shows diagrams of a constitution for one picture element ofthe liquid crystal panel of Embodiment 1-3;

[0038]FIG. 7 shows diagrams of a constitution for one picture element ofthe liquid crystal panel of Embodiment 1-4;

[0039]FIG. 8 shows diagrams of a constitution for one picture element ofthe liquid crystal panel of Embodiment 1-5;

[0040]FIG. 9 shows diagrams of a constitution for one picture element ofthe liquid crystal panel of Embodiment 1-6;

[0041]FIG. 10 is a sectional view of a liquid crystal device ofEmbodiment 1-7;

[0042]FIG. 11 is a sectional view of a liquid crystal device ofEmbodiment 1-8;

[0043]FIG. 12 is a sectional view of a liquid crystal device ofEmbodiment 1-9;

[0044]FIG. 13 is a diagram illustrating a circuitry of the pictureelement of a liquid crystal device of Embodiment 2-1 and equivalent;

[0045]FIG. 14 shows diagrams illustrating the structure of the pictureelement of the same;

[0046]FIG. 15 is a diagram illustrating dimensions of the pictureelement of the same;

[0047]FIG. 16 is a diagram likewise illustrating the condition andoperation of a voltage applied or added to the parts between the pictureelements;

[0048]FIG. 17 is a diagram likewise illustrating the condition andoperation of a voltage applied of Embodiment 2-2;

[0049]FIG. 18 is a block diagram of control means of a liquid crystaldevice of the above-mentioned embodiment;

[0050]FIG. 19 is a diagram illustrating a correlation between a dutyratio and a transition completion time in the primary potentialdifference application step in Embodiment 2-2;

[0051]FIG. 20 is a diagram likewise illustrating the time tr and tfrequired for potential difference Vpc between the pixel electrode andthe opposing electrode to be modulated;

[0052]FIG. 21 is a diagram likewise illustrating the embodied circuitry;

[0053]FIG. 22 is a diagram likewise illustrating the condition andoperation of a voltage applied of Embodiment 2-3;

[0054]FIG. 23 is a diagram illustrating a variant of the embodimentabove;

[0055]FIG. 24 is a diagram illustrating a circuitry of the pictureelement of Embodiment 2-4;

[0056]FIG. 25 shows diagrams illustrating the structure of the pictureelement of the embodiment above;

[0057]FIG. 26 is a diagram illustrating dimensions of the pictureelement of the embodiment above;

[0058]FIG. 27 is a diagram illustrating the operation of Embodiment 2-4;

[0059]FIG. 28 is a time chart of an electrode potential of the pictureelement of Embodiment 2-5;

[0060]FIG. 29 is a diagram showing a measurement result of the relationbetween a potential difference and a transition completion time when thepotential difference between the pixel electrode and the opposingelectrode is modulated;

[0061]FIG. 30 is a time chart of the electrode potential of the pictureelement of Embodiment 2-6;

[0062]FIG. 31 is a time chart of the electrode potential of the pictureelement of Embodiment 2-7;

[0063]FIG. 32 is a time chart of the electrode potential of the pictureelement of Embodiment 2-8;

[0064]FIG. 33 is a time chart of the electrode potential of the pictureelement of Embodiment 2-9;

[0065]FIG. 34 is a time chart of the electrode potential of the pictureelement of Embodiment 2-10;

[0066]FIG. 35 is a diagram illustrating the measurement values oftransition completion time in Embodiment 2-5 to Embodiment 2-11 when thedriving time required for the transition of the liquid crystal layerinto the bend configuration is measured from the primary potentialdifference application step and when the driving time is measured fromthe secondary potential difference application step;

[0067]FIG. 36 is a time chart of the electrode potential of the pictureelement of Embodiment 2-11;

[0068]FIG. 37 is a time chart of Embodiment 3-1; and

[0069]FIG. 38 is a diagram illustrating the circuitry of the embodimentabove.

DESCRIPTION OF REFERENCE NUMERALS

[0070]1 First substrate;

[0071]2 Second substrate;

[0072]3 Pixel electrode;

[0073]21 Transparent pixel electrode;

[0074]5 Liquid crystal layer;

[0075]6 Pixel transistor;

[0076]7 Source line, Source line electrode;.

[0077]70 Source line forming metallic coating;

[0078]71 Source line;

[0079]8 Gate line, Gate line electrode;

[0080]81 Former gate line;

[0081]9 Opposing electrode;

[0082]10 Common electrode;

[0083]11 Black matrix;

[0084]12 Color filter;

[0085]64 Channel protecting layer;

[0086]65 a-Si layer;

[0087]66 n+a-Si layer;

[0088]76 Insulating layer between source line electrode and liquidcrystal layer;

[0089]86 Insulating layer between gate line electrode and a-Si layer;

[0090]87 Insulating layer;

[0091] Vcc Potential of common electrode;

[0092] Vc Potential of opposing electrode;

[0093] Vg Potential of gate line;

[0094] Vs Potential of source line

[0095] Vp Potential of pixel electrode;

[0096] Vpc Potential difference between pixel electrode and opposingelectrode;

[0097] Tc Plain image display period;

[0098] Cgd Capacity between gate line and pixel electrode;

[0099] Cst Storage capacity between pixel electrode and commonelectrode;

[0100] Clc Liquid crystal capacity between pixel electrode and opposingelectrode;

[0101] Cgs Capacity between gate line and source line;

[0102]204 Liquid crystal panel controller; and

[0103]205 Liquid crystal panel

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0104] In the following, the present invention will be described on thebasis of the embodiments.

First Inventive Group

[0105] The first inventive group is mainly characterized in that thestructure of an insulating layer of pixel elements is so designed that ahigh voltage can be applied to a liquid crystal layer for transitionthereof.

[0106] In the following, the first inventive group will be described onthe basis of the embodiments.

Embodiment 1-1

[0107] “Embodiment 1-1” means “a first embodiment of the first inventivegroup”. It follows that “a second embodiment of the first inventivegroup” is presented as “Embodiment 1-2”. The same applies to the otherinventive group.

[0108] Picture elements having circuitry are, in practical, formed on asubstrate to be arranged vertically, horizontally, in rows and incolumns, and further in layers in some cases. Such is, however, theobvious matter, so that illustration thereof is omitted for avoidance ofbotheration. The same applies to the other inventive group and otherembodiments.

[0109]FIG. 2 (1) shows a plan view of the structure of a conventionalliquid crystal panel for each picture element and FIG. 2 (2) shows asectional view of a part of transistor element taken along line of A-A.In this diagram, 21 denotes a transparent pixel electrode. 3 denotes anpixel electrode. 5 denotes a liquid crystal layer. 64 denotes a channelprotecting layer. 65 denotes a a-Si (amorphous silicone) layer. 66denotes a n+a-Si layer. 7 denotes a source line electrode. 76 denotes aninsulating layer between the source line electrode and the liquidcrystal layer. 8 denotes a gate line electrode. 86 denotes an insulatinglayer between the gate line electrode and the a-Si layer. 9 denotes anopposing electrode.

[0110] In FIG. 3, capacitive load between the gate line electrode andthe opposing electrode of the liquid crystal panel shown in FIG. 2 isschematically illustrated.

[0111] In this diagram, 8 denotes the gate line electrode and 9 denotesthe opposing electrode. C1 denotes capacitive load of the liquid crystallayer. C2 denotes capacitive load of the insulating layer between thesource line electrode and the liquid crystal layer. C3 denotescapacitive load of the insulating layer between the gate line electrodeand the a-Si layer.

[0112]FIG. 4 (1) shows a plan view of the structure of the liquidcrystal panel of this embodiment for each picture element and FIG. 4 (2)shows a sectional view of the same taken along line of A-A.

[0113] In this diagram, 8 denotes the gate line electrode. 7 denotes thesource line electrode, 3 denotes the pixel electrode, 64 does thechannel protecting layer. 65 denotes the a-Si layer, 66 denotes then+a-Si layer. 86 denotes the first insulating layer between the gateline electrode and the a-Si layer. 762 denotes a second insulating layerbetween the source line electrode and the liquid crystal layer. 5denotes a liquid crystal layer, 9 denotes the opposing electrode, 21denotes the transparent pixel electrode. 862 denotes a second insulatinglayer between the gate line electrode and the a-Si layer. 761 denotes afirst insulating layer between the source line electrode and the a-Silayer.

[0114] In the following, operation of this embodiment will be describedwith reference to these three diagrams.

[0115] In FIG. 2, when a voltage V is applied to the gate line electrode8 and the opposing electrode 9, divided voltages which are determined bya ratio of the capacitive loads among the liquid crystal layer 5, theinsulating layer 762 between the source line electrode 7 and the liquidcrystal layer, and the insulating layer 86 between the gate lineelectrode and the a-Si layer are applied to the respective layers. Thepartial pressures are expressed by V1, V2 and V3. The relation amongthem is described with reference to FIG. 3.

[0116] The capacitive load value C per unit area S is shown by thefollowing equation (1-1),

C=ε0×ε×S/1  (Eq.1-1)

[0117] where ε is a relative dielectric constant of the layer, 1 isthickness of the layer, and εis a dielectric constant of vacuum.

[0118] The partial pressure V1 of the capacitive loads C1, C2 and C3connected in series is shown by the following equation (1-2),

V 1=V*C 2*C 3/(C 1*C 2+C 2*C 3+C 3*C 1)  (Eq. 1-2).

[0119] The partial pressure V1 of the equation (1-2) is shown by thefollowing equation (1-3),

V 1=V*ε2*ε3*l 1/(ε1*ε2*l 3+ε2*ε3*l 1+ε3*ε1*l 2)  (Eq. 1-3),

[0120] where ε1, ε2, ε3, l1, l2, and l3 are relative dielectricconstants and thickness of the liquid crystal layer 5 and the insulatinglayers 762 an 86, respectively. $\begin{matrix}\begin{matrix}{{{E1}\quad \left( {{electric}\quad {field}\quad {intensity}} \right)} = {{V1}/11}} \\{= {V*ɛ\quad 2*ɛ\quad {3/\left( {{ɛ\quad 1*ɛ\quad 2*{l3}} +} \right.}}} \\\left. {{ɛ\quad 2*ɛ\quad 3*{l1}} + {ɛ\quad 3*ɛ\quad 1*{l2}}} \right) \\{= {V/\left( {{l1} + {{l2}*ɛ\quad {1/ɛ}\quad 2} +} \right.}} \\\left. {{l3}*ɛ\quad {1/ɛ}\quad 3} \right)\end{matrix} & \left( {{{Eq}.\quad 1}\text{-}4} \right)\end{matrix}$

[0121] In the structure of FIG. 4, the insulating layer between the gateline electrode and the a-Si layer and the insulating layer between thesource line electrode and the liquid crystal layer are formed into abilayer and are patterned, whereby thickness of the insulating layerbetween the gate line electrode and the liquid crystal layer is reduced,while the insulation between the gate line electrode and the a-Si layerand the insulation between the source line electrode and the liquidcrystal layer are kept equivalent to the conventional insulation. Withthis structure, the denominator in the Eq. 1-4 of the electric fieldintensity E1 is reduced and, accordingly, the intensity of the electricfield applied to the liquid crystal layer is increased, thus enablingthe transition of the liquid crystal layer into the bend configurationat a high speed.

[0122] Relative dielectric constant of the liquid crystal layer variesto the extent of about 3 to about 8, depending on transmittance of theliquid crystal. When the relative dielectric constants of SiOx, SiNx andTaOx used as the insulating layer are about 3.9, about 6.4 and about 23,respectively, and the variation in relative dielectric constant of theliquid crystals is uniform, the intensity of the electric field appliedto the liquid crystal layer of FIG. 13 often becomes higher than theintensity of the electric field (Eq. 1-4) of the conventional structure.To apply a highest possible electric field intensity to the liquidcrystal layer is very effective for causing the transition of the liquidcrystal layer having the bend configuration from its initial homogeneousstate into the bend configuration at high speed. Accordingly, formingthe insulating layer to have a reduced thickness as in this embodimentforms a very effective means therefor.

Embodiment 1-2

[0123] Shown in FIG. 5 is a schematic diagram of the structure ofEmbodiment 1-2.

[0124] In this diagram, 8 denotes the gate line electrode. 7 denotes thesource line electrode, 3 denotes the pixel electrode. 64 denotes thechannel protecting layer, 65 denotes the a-Si layer. 66 denotes then+a-Si layer, 86 denotes the insulating layer between the gate lineelectrode and the a-Si layer. 76 denotes the insulating layer betweenthe source line electrode and the liquid crystal layer. 5 denotes theliquid crystal layer, 9 denotes the opposing electrode. 21 denotes thetransparent pixel electrode. A denotes a line along which the section istaken.

[0125] In the 1st embodiment above (Embodiment 1-1 is abbreviated likethis, because it is obvious beyond misunderstanding, and the sameapplies to the following), the insulating layers are formed into thebilayer. Instead of this constitution, the insulating layer between thegate line electrode and the liquid crystal layer may be reduced inthickness by patterning, as shown in FIG. 5, to produce the same effect.

Embodiment 1-3

[0126] Shown in FIG. 6 is a schematic diagram of the structure ofEmbodiment 1-3.

[0127] In this diagram also, 8 denotes the gate line electrode. 7denotes the source line electrode, 3 denotes the pixel electrode. 64denotes the channel protecting layer, 65 denotes the a-Si layer, 66denotes the n+a-Si layer. 86 denotes the insulating layer between thegate line electrode and the a-Si layer, 76 denotes the insulating layerbetween the source line electrode and the liquid crystal layer. 5denotes the liquid crystal layer, 9 denotes the opposing electrode. 21denotes the transparent pixel electrode. A denotes the line along whichthe section is taken.

[0128] In this structure, the gate line electrode is formed to have athickened layer part at a specified part thereof so that the liquidcrystal layer on the gate line is reduced in thickness. This produces anincreased electric field intensity applied to the liquid crystal layer,so that the transition of the liquid crystal layer to the bendconfiguration is speeded up.

[0129] The gate line electrode usually has a layer thickness of theorder of 0.2 μm to about 0.6 μm. When the gate line electrode isthickened about twice, the thickness of the liquid crystal layer can bereduced by the order of 0.5 μm.

Embodiment 1-4

[0130] Shown in FIG. 7 is a schematic diagram of the structure ofEmbodiment 1-4.

[0131] In this diagram also, 8 denotes the gate line electrode. 7denotes the source line electrode, 3 denotes the pixel electrode. 64denotes the channel protecting layer, 65 does the a-Si layer, 66 denotesthe n+a-Si layer. 86 denotes the insulating layer between the gate lineelectrode and the a-Si layer. 76 denotes the insulating layer betweenthe source line electrode and the liquid crystal layer. 5 denotes theliquid crystal layer, 9 denotes the opposing electrode. 21 denotes thetransparent pixel electrode. A denotes the line along which the sectionis taken. 70 denotes a source line forming metal laminated on the gateline electrode in electrical contact therewith.

[0132] In this structure, the source line forming metal is laminated onthe gate line forming metal in electrical contact therewith, to form apartially contacting gate line. This structure provides a substantiallyincreased thickness of the gate line electrode to produce a reducedthickness of the liquid crystal layer on the gate line. This produces anincreased electric field intensity applied to the liquid crystal layer,so that the transition of the liquid crystal layer to the bendconfiguration is speeded up.

[0133] The source line electrode usually has a layer thickness of theorder of 0.2 μm to about 0.6 μm. Accordingly, the thickness of theliquid crystal layer can be reduced to that extent.

Embodiment 1-5

[0134] Shown in FIG. 8 is a schematic diagram of the structure ofEmbodiment 1-5.

[0135] In this diagram also, 8 denotes the gate line electrode. 7denotes the source line electrode, 3 denotes the pixel electrode. 64denotes the channel protecting layer, 65 denotes the a-Si layer. 66denotes the n+a-Si layer. 86 denotes the insulating layer between thegate line electrode and the a-Si layer. 76 denotes the insulating layerbetween the source line electrode and the liquid crystal layer. 5denotes the liquid crystal layer, 9 denotes the opposing electrode. 21denotes the transparent pixel electrode. A does the line along which thesection is taken. 713 denotes a source line forming metal laminated ontothe gate line electrode in non-electrical contact therewith.

[0136] In this structure, the source line forming metal is interposedbetween the gate line electrode and the opposing electrode to provideelectrical isolation therebetween, thereby forming a non-contact typegate line. This structure provides a reduced thickness of the liquidcrystal layer on the gate line to thereby produce increased electricfield intensity applied to the liquid crystal layer, so that thetransition of the liquid crystal layer to the bend configuration isspeeded up.

Embodiment 1-6

[0137] Shown in FIG. 9 is a schematic diagram of the structure ofEmbodiment 1-6.

[0138] In this diagram, 1 denotes a first substrate. 8 denotes the gateline electrode. 7 denotes the source line electrode, 6 denotes a pixeltransistor. 2 denotes a second substrate. 91 denotes a first opposingelectrode formed at a position to confront the gate line electrode onthe first substrate, 92 denotes a second opposing electrode electricallyisolated from the first opposing electrode. In this structure of theopposing electrodes being divided, since the first opposing electrodeand the second opposing electrode are electrically isolated from eachother, the pixel electrode and the pixel transistor are prevented frombeing affected by voltage variation through the capacitive loads of theliquid crystal layer and the insulating layer, while a given electricfield intensity is given to the liquid crystal layer over the gate lineelectrode. This enables the transition of the liquid crystal layer tothe bend configuration to be speeded up. In the normal image displayperiod, the potential of the first opposing electrode and the potentialof the second opposing electrode are made equal to each other. This canproduce exactly the same image quality as that of the conventionalliquid crystal display device having the opposing electrodes to which nopatterning is given.

Embodiment 1-7

[0139] Shown in FIG. 10 is a sectional view of the liquid crystaldisplay device of Embodiment 1-7.

[0140] In this diagram, 1 denotes the first substrate. 8 denotes thegate line electrode, 7 denotes the source line electrode. 87 denotes theinsulating layer. 2 denotes the second substrate, 11 denotes a blackmatrix metal formed at a position to confront the gate line electrode onthe first substrate. 12 denotes a color filter, 5 denotes the liquidcrystal layer. 91 denotes a first-layered opposing electrodesubstantially uniformly formed over the whole area of the secondsubstrate and 92 a second-layered opposing electrode formed at aposition to confront the gate line on the first substrate. In thisstructure of the opposing electrodes being thickened at the confrontingpositions, the opposing electrodes confronting each other over the gateline are formed in a two-layer structure to produce a reduced thicknessof the liquid crystal layer over the gate line. This produces anincreased electric field intensity of the liquid crystal layer, so thatthe transition of the liquid crystal layer to the bend configuration isspeeded up.

Embodiment 1-8

[0141] Shown in FIG. 11 is a sectional view of the liquid crystaldisplay device of Embodiment 1-8.

[0142] In this diagram also, 1 denotes the first substrate. 8 denotesthe gate line electrode, 7 denotes the source line electrode. 87 denotesthe insulating layer. 2 denotes the second substrate, 11 denotes theblack matrix metal formed at a position to confront the gate lineelectrode on the first substrate. 121 denotes a first-color (e.g. red)color filter, 122 denotes a second-color (e.g. blue) color filter. 9denotes the opposing electrode, 5 does the liquid crystal layer.

[0143] In this structure, color filter forming resin is laminated on thesecond substrate at its portion to confront the gate line electrode onthe first substrate, whereby the opposing electrode on that portion ismade protuberant to produce a reduced thickness of the liquid crystallayer over the gate line. This produces an increased electric fieldintensity of the liquid crystal layer, so that the transition of theliquid crystal layer to the bend configuration is speeded up.

Embodiment 1-9

[0144] Shown in FIG. 12 is a sectional view of the liquid crystaldisplay device of Embodiment 1-9.

[0145] In this diagram also, 1 denotes the first substrate. 8 denotesthe gate line electrode, 7 denotes the source line electrode. 87 denotesthe insulating layer; 2 does the second substrate. 11 denotes the blackmatrix metal formed at a position to confront the gate line electrode onthe first substrate, 12 denotes the color filter. 111 denotes apillar-shaped spacer formed at a position to confront the gate line onthe first substrate. 9 denotes the opposing electrode. 5 denotes theliquid crystal layer.

[0146] In this structure, the pillar-shaped spacer is formed on thesecond substrate at its portion to confront the gate line electrode onthe first substrate and the opposing electrode is formed between thepillar-shaped spacer and the liquid crystal layer, whereby the liquidcrystal layer over the gate line is reduced in thickness. This producesincreased electric field intensity of the liquid crystal layer, so thatthe transition of the liquid crystal layer to the bend configuration isspeeded up.

[0147] While various structures of the liquid crystal panel have beendescribed above with reference to the nine embodiments from the firstembodiment to the ninth embodiment, two or more of the embodiments maybe combined to provide a reduced thickness of the liquid crystal layerover the gate line. Using those structures in combination can easilyproduce the enhanced effect, as compared with using any one embodimentsingularly. Additionally, when the opposing electrode is divided and anyselected voltage is applied to the electrode confronting the gate line,the effect is further enhanced.

Second Inventive Group

[0148] The second inventive group is mainly characterized in that ahigher voltage is applied between the pixel electrode and the opposingelectrode for the transition of the liquid crystal layer than for thenormal image display period or a secondary voltage is applied andfurther ingenuity is applied to the means therefore and the duty ratio.

Embodiment 2-1

[0149]FIG. 13 shows a constitution of the liquid crystal device of thisembodiment around the circuit of the picture element. In this diagram, 3denotes the pixel electrode. 6 denotes the pixel transistor. 7 denotesthe source line. 71 denotes the next source line. 8 denotes the gateline. 81 denotes the previous gate line. 9 denotes the opposingelectrode. 10 is a common electrode connected to the total storagecapacity. Cgd denotes a capacity between gate and drain of the pixeltransistor. Cst denotes a storage capacity connected to the pixelelectrode and formed between the pixel electrode and the commonelectrode. Clc denotes a capacity of the liquid crystal layer. Cgs is acapacity between gate and source of the pixel transistor.

[0150]FIG. 14 schematically shows in plan and section the principalstructure of the picture element. In this diagram, 6 denotes the pixeltransistor. 21 denotes the transparent pixel electrode. Cst denotes thestorage capacity connected to the pixel electrode and formed between thepixel electrode and the common electrode. Clc denotes the capacity ofthe liquid crystal layer. 7 denotes the source line; 71 denotes the nextsource line. 8 denotes the gate line, 81 denotes the previous gate line.9 denotes the opposing electrode. 10 denotes the common electrodeconnected to the total storage capacity.

[0151]FIG. 15 shows one example of dimensions per picture element. Inthis diagram, Wt denotes a width of the picture element. Lt denotes alength of the picture element. Wp denotes a width of the pixelelectrode. Lp denotes a length of the pixel electrode. Ws denotes awidth of the source line. Wg is a width of the gate line. The total areaper picture element is 30,000[μm²] and the area of the pixel electrodeis 18,224 μm² which is 60.7% of the total area of one picture element.

[0152] Operation of the liquid crystal device of this embodiment shownin FIGS. 13, 14 and 15 is illustrated in FIG. 16.

[0153] In FIG. 16, Vg denotes a voltage of the gate line. Vs denotes avoltage of the source line. Vp is a voltage of the pixel electrode. Vccis a voltage of the common electrode. Vc is a voltage of the opposingelectrode.

[0154] In the normal image display, the voltage Vg of the gate line ismodulated until the pixel transistor is put in the ON mode, to chargethe pixel electrode 21, the storage capacity Cst and the liquid crystalcapacity Clc with the voltage Vs of the source line. The voltage Vp ofthe pixel electrode comes to be equal to the voltage Vs of the sourceline.

[0155] The voltage Vc of the opposing electrode should preferably be setwithin a range within which the transmittance of the liquid crystal isallowed to fully vary between the voltage of the opposing electrode andthe voltage Vp of the pixel electrode. Usually, the potential differenceVpc between Vc and Vp is set in the range of the order of 0V to 5V. Thetransition of the liquid crystal layer to the bend configurationrequires the different potential difference continuous application stepof continuously applying a further higher potential difference to theliquid crystal layer. The potential difference and the time required forthe transition of the liquid crystal layer into the bend configurationvaries depending on the liquid crystal material used. It isexperimentally confirmed that there is some material that enables thetransition to be completed within 1 second by applying a potentialdifference of 6V or more between the pixel electrode and the opposingelectrode. A shortest possible transition time is desirable for thetransition of the liquid crystal display device. The transition time isdesirably within the range of from a few seconds to ten seconds, whichhowever requires the application of a large potential difference (theorder of 20V to 30V) or the choice of the liquid crystal material. Thepotential difference required for the transition of the liquid crystallayer to the bend configuration is desirably applied to a largestpossible area thereof, and it is most effective in terms of theavailability of area that that potential difference is applied betweenthe pixel electrode and the opposing electrode, as shown in FIG. 15.

Embodiment 2-2

[0156] Operation of the second embodiment will be illustrated in FIG. 17by combined use of FIGS. 13, 14 and 15.

[0157] In FIG. 17, Vg denotes a voltage of the gate line. Vs denotes avoltage of the source line. Vp is a voltage of the pixel electrode. Vccis a voltage of the common electrode. Vc is a voltage of the opposingelectrode. Operation of the liquid crystal panel having thisconstitution in the normal image display is the same as the operation ofthe first embodiment. The potential difference Vpc between Vc and Vp isin the range of 0V to 5V. When a primary potential difference of notless than 6V is continuously applied between the pixel electrode and theopposing electrode in order to cause the transition of the liquidcrystal layer to the bend configuration, depending on the structure ofthe liquid crystal panel or the liquid crystal material, the transitionis sometimes partly deadlocked, so that the transition at that part maynot be effected even after the passage of 10 seconds or more. In thiscondition of panel structure or liquid crystal material, the voltage Vcof the opposing electrode is brought close to the voltage Vp of thepixel electrode and thereby the potential difference Vpc applied to theliquid crystal layer is modulated to a secondary small potentialdifference to return the alignment of the liquid crystal elements totheir original state, first, and then the primary high potentialdifference is applied again to the liquid crystal layer. This producesthe result that even if the liquid crystal elements are first returnedto their original state and then that potential difference is appliedagain thereto, since the liquid crystal elements that were originallychanged into the bend state are easily changed into the bend state, thetransition is effected shortly after the potential difference is appliedagain, and as such can allow the deadlocked part to be easily changed tothe bend state by newly applying the potential difference. Accordingly,the transition to the bend configuration can be effected over the wholearea of the panel in a short time.

[0158]FIG. 18 shows an example of the constitution of control means ofthe liquid crystal device according to the present invention.

[0159] In this diagram, 205 denotes the liquid crystal panel. 204denotes a liquid crystal panel controller. 203 denotes power-supplyvoltage generating circuits. A starting switch 210 is connected to theliquid crystal panel controller 204 from outside. The starting switch210 is connected to a counter 211 and in turn to a switching means A 212arranged in the interior of the liquid crystal panel controller 204.Immediately after the startup, a predetermined time is counted by thecounter and, then, picture signals from a normal image signal generatingpart 213 are applied to the liquid crystal panel 205. In the counting ofthe predetermined time, a switching means B denoted by 217 switchesbetween a 1st voltage generating means 214 and a 2nd voltage generatingmeans 215 in a predetermined period preset by the period counter 216.These voltage generating means do not necessarily generate a singlevoltage. The liquid crystal panel 205 takes an active matrix mode, sothat the effective potential difference between the pixel electrode andthe opposing electrode applied to the liquid crystals in the panel isthe key factor. Therefore, the switching is performed by combining anyrequired voltages selected from not only the voltage of the opposingelectrode but also the voltages of the source line, gate line and commonelectrode of the storage capacity mentioned later which are criticalfactors for determining the voltage of he pixel electrode.

[0160] The predetermined time immediately after the startup mentionedherein indicates the time of the order of about 0.1 to 10 seconds, andthe predetermined period preset by the period counter 216 indicates thetime period of the order of about 0.1 to 5 seconds.

[0161] In this embodiment, since the time required for the potentialdifference Vpc between the pixel electrode and the opposing electrode tobe modulated to the secondary potential difference is the time requiredfor the transition of the liquid crystal elements to the bendconfiguration to be returned to their original state, it should be madeequal to or shorter than the time for the primary potential differenceto be applied between the pixel electrode and the opposing electrode, tocomplete the transition of the liquid crystal elements to the bendconfiguration in the entire liquid crystal panel in a short time. Asshown in FIG. 19, when the duty ratio exceeds 0.5 in the primarypotential difference application step in which the higher primarypotential difference is applied to Vpc, the transition time issignificantly shortened. It takes about 0.1 second to 3 seconds for theprimary potential difference application step. Ups and downs in athrough rate of voltage variation of the opposing electrode generated atthe time of switching between the primary potential differenceapplication step and the secondary potential difference application stepdoes not directly affect on the to-the-bend configuration transitiontime. Thus, even when the voltage is gently varied by use of a driveelement having only a small current driving capability, to drive a highload electrode such as the opposing electrode, the substantially sameeffect can be provided. As shown in FIG. 20, when the potentialdifference Vpc is varied in the period T repeatedly controlling step,prompt transition can be provided until the time tr and tf required forthe potential difference to be varied reach 30% of the respective periodT.

[0162] The current i [A] required for the capacity C [F] to be modulatedto V [V] in t second by use of the circuit as shown in FIG. 21 is givenby the following equation:

i=C*V/t

[0163] It follows from this that the current driving capability requiredfor the opposing electrode having the capacity of 10 [uF] to bemodulated to 10 [V] in 300 msec. is 0.33 [mA]. Accordingly, the circuitcan be formed by a current driving element such as a general operationalamplifier or a low power consumption operational amplifier. Though notshown, the capacity element may be driven by a pulsed signal source andserial resistance.

Embodiment 2-3

[0164] Referring to FIGS. 13, 14 and 15, there is shown the commonelectrode's potential difference variation using mode as the thirdembodiment in which the primary potential difference is increased by useof the potential variation of the common electrode in the firstembodiment, and the operation is illustrated in FIG. 22. This embodimentis identical in constitution to the first embodiment.

[0165] In FIG. 22, Vg denotes a voltage of the gate line. Vs denotes avoltage of the source line. Vp denotes a voltage of the pixel electrode.Vcc denotes a voltage of the common electrode. Vc denotes a voltage ofthe opposing electrode.

[0166] During the time during which the pixel transistor is in the ONmode, the potential Vs of the source line is written to the pixelelectrode. When the pixel transistor is put in the OFF mode, thepotential Vp of the pixel electrode is varied only by the extent of apunch-through voltage ΔVp1 calculated from the following Equation 2-1 inaccordance with the voltage variationΔVg of the gate line. Further, whenthe potential Vcc of the common electrode which forms the electrode ofstorage capacity during the time during which the pixel transistor is inthe OFF mode is varied only by the extent of ΔVcc, a punch-throughvoltage ΔVp2 calculated from the following Equation 2-2 is generated inthe pixel electrode. For the signal variation illustrated in thisdiagram, a potential higher than the potential Vs written from thesource line can be applied to the pixel electrode by rendering ΔVp2larger ΔVp1. This allows the potential difference Vpc between the pixelelectrode and the opposing electrode to increase further, so that thetime required for the transition of the liquid crystal layer into thebend configuration is shortened.

ΔVp 1=ΔVg*Cgd/(Cst+Clc+Cgd)  Eq. 2-1

ΔVp 2=ΔVcc*Cst/(Cst+Clc+Cgd)  Eq. 2-2

[0167] In this case, even when the voltage of the common electrode ismade equal to that of the gate signal, as shown in FIG. 23, Vpc cansubstantially be increased and also the scale of the power supplycircuit can be reduced by common use of the voltage.

Embodiment 2-4

[0168]FIG. 24 is a diagram illustrating the constitution for one pictureelement of the liquid crystal panel. In the diagram, 6 denotes the pixeltransistor. 3 denotes the pixel electrode, Cgd denotes the capacitybetween gate and drain of the pixel transistor. Cst denotes storagecapacity connected to the pixel electrode and formed between the pixelelectrode and the previous gate line, Clc denotes the capacity of theliquid crystal layer. Cgs denotes capacity between gate and source ofthe pixel transistor. 7 denotes the source line, 71 denotes the nextsource line. 8 denotes the gate line, 81 denotes the previous gate line.11 denotes the opposing electrode. The liquid crystal panel of thisconstitution, which is called the previous gate mode, can eliminate theneed of the common electrode to enhance the aperture ratio, as comparedwith the constitution of FIGS. 13 and 14.

[0169]FIG. 25 schematically illustrates in plan and section the pixelstructure. 6 denotes the pixel transistor. 21 denotes the transparentpixel electrode. Cst denotes the storage capacity connected to the pixelelectrode and formed between the pixel electrode and the previous gateline. Clc denotes the capacity of the liquid crystal layer. 7 denotesthe source line, 71 denotes the next source line. 8 denotes the gateline, 81 denotes the previous gate line. 9 denotes the opposingelectrode.

[0170]FIG. 26 shows one example of dimensions per picture element. Wtdenotes the width of the picture element. Lt denotes the length of thepicture element. Wp denotes the width of the pixel electrode. Lp denotesthe length of the pixel electrode. Ws denotes the width of the sourceline Wg is the width of the gate line. Wst is a lengthwise side of thestorage capacity part. Lst is a gap between the pixel electrode and thegate line. The total area per picture element is 30,000[μm²] and thearea of the pixel electrode is 18,564 μm² which is 61.9% of the totalarea of one picture element.

[0171] Referring to FIGS. 24, 25 and 26, there is shown the gate line'spotential difference variation using mode as the fourth embodiment inwhich the primary potential difference is increased by use of thepotential variation of the previous gate line in the second embodiment,and the operation is illustrated in FIG. 27.

[0172] In this diagram, Vg denotes the voltage of the gate line. Vsdenotes the voltage of the source line 7. Vp denotes the voltage of thepixel electrode. Vg− denotes a voltage of the previous gate line 81. Vcdenotes the voltage of the opposing electrode.

[0173] In the normal image display, the voltage Vg of the gate line ismodulated until the pixel transistor is put in the ON mode, to chargethe transparent pixel electrode 21, the storage capacity Cst and theliquid crystal capacity Clc with the voltage Vs of the source line. Thevoltage Vp of the transparent pixel electrode 21 comes to be equal tothe voltage Vs of the source line 7.

[0174] When the pixel transistor is put into the OFF mode, the potentialVp of the pixel electrode is varied only by the extent of apunch-through voltage ΔVp3 calculated from the following Equation 2-3 inaccordance with the voltage variation ΔVg of the gate line. Further,when the potential Vg− of the previous gate line which forms theelectrode of storage capacity during the time during which the pixeltransistor is in the OFF mode is varied only by the extent of ΔVg−, apunch-through voltage ΔVp4 calculated from the following Equation 2-4 isgenerated in the pixel electrode. For the signal variation illustratedin FIG. 27, a potential higher than the potential Vs written from thesource line can be applied to the pixel electrode by rendering ΔVp4larger ΔVp3. This allows the potential difference Vpc between the pixelelectrode and the opposing electrode to increase further, so that thetime required for the transition of the liquid crystal layer into thebend configuration is shortened.

ΔVp 3=ΔVg*Cgd/(Cst+Clc+Cgd)  Eq. 2-3

ΔVp 4=ΔVg−*Cst/(Cst+Clc+Cgd)  Eq. 2-4

[0175] As shown in FIG. 26, the proportion of the area of the pixelelectrode to the total area of a single picture element is rather largeof 61.9%, so that it is very effective to apply a large potentialdifference between the pixel electrode and the opposing electrode.

[0176] In the liquid crystal panel thus constituted, the potentialdifference Vpc between Vc and Vp in the normal image display is in therange of 0V to 5V. When a potential difference of not less than 6V isapplied between the pixel electrode and the opposing electrode by D.C.,in order to cause the transition of the liquid crystal layer to the bendconfiguration, depending on the structure of the liquid crystal panel orthe liquid crystal material, the transition is sometimes partlydeadlocked, so that the transition of the liquid crystal elements atthat part may not be effected even after the passage of 10 seconds ormore. In this condition of panel structure or liquid crystal material,the voltage Vc of the opposing electrode is brought close to the voltageVs of the pixel electrode, so that the potential difference Vpc appliedto the liquid crystal layer is modulated to a secondary small potentialdifference to return the alignment of the liquid crystal elements totheir original state and, then, the primary high potential difference isapplied again to the liquid crystal layer. This allows the deadlockedpart to easily changed to the bend state by newly applying the potentialdifference and, accordingly, the transition to the bend configurationcan be effected over the whole area of the panel in a short time.

[0177] While in this embodiment, the storage capacity is providedbetween the pixel electrode and the previous gate line, the storagecapacity may alternatively be provided between the pixel electrode andthe next gate line. This alternation can also produce the equivalenteffects in the equivalent operation.

Embodiment 2-5

[0178] With reference to the time chart of the potential of the pixelelectrode shown in FIG. 28 and the electrical schematic diagram shown inFIG. 13, operation of Embodiment 2-5 will be described.

[0179] In FIG. 28, the potential of the opposing electrode is depictedby a thick dotted line; the potential of the gate line is depicted by athin dotted line; the potential of the source line is depicted by a thinsolid line; and the potential of the pixel electrode is depicted by athick solid line. Vpc at the bottom of the diagram denotes variation ofpotential difference between the pixel electrode and the opposingelectrode. Tc denotes a normal image display period. T₁₂ denotes a firstsecondary potential difference application step. T₁₁ denotes a firstprimary potential difference application step. T₂₂ denotes a secondsecondary potential difference application step. T₂₁ denotes a secondprimary potential difference application step. Variation factors ofvarious potentials of the pixel electrode are shown herein.

[0180] In this diagram, the steps of T₁₂, T₁₁, T₂₂, and T₂₁ are repeatedin the repeat control step. When the first secondary potentialdifference application step T₁₂ starts in the first driving period foreffecting the transition of liquid crystal layer to the bendconfiguration, the potential of the opposing electrode is modulated to asecond potential, different from that in the normal image displayperiod. The potential of the pixel electrode comes into connection withthe opposing electrode through the liquid crystal capacity. At thismoment, the pixel transistor is in the OFF mode and no current issupplied thereto. Accordingly, the potential varies only by the extentof ΔVp5 shown in the following Eq. (2-5) with respect to the variationof ΔVcom in the potential of the opposing electrode in the direction inwhich the potential of the opposing electrode varied, as illustrated atthe left side of the period of T₁₂ when viewed in the diagram.

ΔVp 5=ΔVcom*Clc/(Clc+Cst+Cgd)  (Eq. 2-5)

[0181] The potential variation by which the potential variation ΔVg hasan influence on the pixel electrode when the gate line switches thepixel transistor from ON to OFF is given as ΔVp6 shown in the followingEq. (2-6).

[0182] When the potential of the source line is modulated to be equal tothe potential of the opposing electrode increased by ΔVp6 and then thepixel transistor is switched to OFF, the potential of the pixelelectrode lowers by the extent of ΔVp6, as illustrated potentialvariation of the gate electrode in the period T₁₂ at the center thereof,so that the potential difference between the pixel electrode and theopposing electrode becomes the secondary potential difference ofsubstantially zero.

ΔVp 6=ΔVg*Cgd/(Clc+Cst+Cgd)  (Eq. 2-6)

[0183] Subsequently, the secondary potential difference of substantiallyzero in potential difference between the potential of the pixelelectrode and the potential of the opposing electrode is produced in thefirst secondary potential difference application step T₁₂, except duringthe charging sub-step during which the pixel transistor is in the ONmode to charge the pixel electrode with the potential of the sourceline.

[0184] After the shift from the first secondary potential differenceapplication step T₁₂ to the first primary potential differenceapplication step T₁₁ takes place, the potential of the opposingelectrode is modulated to the first potential, in order to modulate thepotential difference between the potential of the pixel electrode andthe potential of the opposing electrode to the primary potentialdifference. Under the influence of this, the potential of the pixelelectrode is varied in the direction in which the potential of theopposing electrode was varied, as illustrated potential variation of theopposing electrode at the left side of the period T₁₁. When thepotential of the source line is modulated to be equal to the potentialof the opposing electrode increased by ΔVp6 and then the pixeltransistor is switched to ON/OFF once in the charging sub-step, as isthe case with the first secondary potential difference application stepT₁₂, the potential of the pixel electrode lowers down to a potentialgenerally equal to the potential of the opposing electrode in thesecondary potential difference application step. In the primarypotential difference application step, however, the potential of theopposing electrode is set so that the potential difference between thepotential of the pixel electrode and the potential of the opposingelectrode can become the primary potential difference which is enoughlarge for the transition of the liquid crystal layer to the bendconfiguration to be effected.

[0185] Subsequently, during the first primary potential differenceapplication step T₁₁, the primary potential difference required for thetransition of the liquid crystal layer to the bend configuration to beeffected is being applied to the potential difference between the pixelelectrode and the potential of the opposing electrode.

[0186] When the second secondary potential difference application stepT₂₂ starts, the potential of the opposing electrode varies, under theinfluence of which the potential of the pixel electrode is varied in thedirection in which the potential of the opposing electrode was varied,as illustrated potential variation of the opposing electrode at the leftside of the period T₂₂. When the pixel transistor is switched to ON/OFFonce in the charging sub-step, the pixel transistor is put into the ONmode, as is the case with the first secondary potential differenceapplication step T₁₂, so that the potential difference between the pixelelectrode and the opposing electrode is modulated to the secondarypotential difference of substantially zero, except during the pixelelectrode being charged with the potential of the source line.

[0187] When the shift from the second secondary potential differenceapplication step T₂₂ to the second primary potential differenceapplication step T₂₁ takes place, the primary potential difference largeenough for the transition of the liquid crystal layer to the bendconfiguration to be effected is applied to the potential differencebetween the pixel electrode and the opposing electrode, as is the casewith the first primary potential difference application step.

[0188] Subsequently, in the repeat control step, the secondary potentialdifference application step and the primary potential differenceapplication step are alternately taken until the completion of thetransition of the liquid crystal layer into the bend configuration. Inthe secondary potential difference application step, the potentialdifference between the pixel electrode and the opposing electrode ismodulated to the secondary potential difference of substantially zero,except in the period from after the start of the period till the firstpixel transistor being turned on and in the period in which the pixeltransistor is in the on mode in the charging sub-step. In the primarypotential difference application step, the primary potential differencelarge enough for the transition of the liquid crystal layer into thebend configuration to be effected is applied between the pixel electrodeand the opposing electrode, except in the period from after the start ofthe period till the pixel transistor being first turned on.

[0189] Thus, the transition of the liquid crystal layer to the bendconfiguration can be effected over whole area of the panel at high speedby alternately controlling the primary potential difference applicationstep in which the potential difference between the pixel electrode andthe opposing electrode is increased to generate the nucleus for the bendconfiguration and enlarge the bend area and the secondary potentialdifference application step in which the potential difference betweenthe pixel electrode and the opposing electrode is decreased so that thepart of the liquid crystal layer where the nucleus for the bendconfiguration was not generated or the bend area was not enlarged can bealigned again.

[0190] It is desirable that the secondary potential difference betweenthe pixel electrode and the opposing electrode is substantially zero inthe secondary potential difference application step. If it falls withinthe range of ±1 V, then there is presented little influence on thein-plane transition completion time, as shown in FIG. 29. There arevariations in storage capacity Cst, liquid crystal capacity Clc andgate-drain capacity Cgd in the interior of the panel as well as betweenthe panels, depending on their thickness and material. Because of this,variation can be caused in the potential variation of ΔVp6 in the pixelelectrode which is affected by the potential variation of the gate line.However, when the variation falls within the range of ±1 V, thepotential of the source line in the secondary potential differenceapplication step need not be modulated for each panel and thus thedriving method using a fixed potential of the source line can bedetermined.

Embodiment 2-6

[0191] Referring to FIGS. 30 and 13, operation of the sixth embodimentwill be described in which the potential of the source line is modulatedin accordance with the ON/OFF timing of the pixel transistor in thesecondary potential difference application step of the fifth embodiment.

[0192] Shown in FIG. 30 is the time chart of the potential of the pixelelectrode shown in FIG. 13.

[0193] In the diagram, the potential of the opposing electrode isdepicted by the thick dotted line; the potential of the gate line isdepicted by the thin dotted line; the potential of the source line isdepicted by the thin solid line; and the potential of the pixelelectrode is depicted by the thick solid line. Vpc at the bottom of thediagram denotes a potential difference between the pixel electrode andthe opposing electrode. Vsc denotes a potential difference between thesource line and the opposing electrode. Tc denotes the normal imagedisplay period. T₁₂ denotes the first secondary potential differenceapplication step. T₁₁ denotes the first primary potential differenceapplication step. T₂₂ denotes the second secondary potential differenceapplication step. T₂₁ denotes the second primary potential differenceapplication step. Variation factors of various potentials of the pixelelectrode are shown herein.

[0194] In this diagram, when the first secondary potential differenceapplication step T₁₂ starts in the driving period for effecting thetransition of liquid crystal layer to the bend configuration, thepotential of the opposing electrode is modulated to the secondpotential, different from that in the normal image display period. Thepotential of the pixel electrode varies only by the extent of ΔVp5 shownin the Eq. (2-5) with respect to the variation of ΔVcom in the potentialof the opposing electrode in the direction in which the potential of theopposing electrode varied, as illustrated potential variation of theopposing electrode. When the potential of the source line is modulatedto be equal to the potential of the opposing electrode increased by ΔVp6and then the pixel transistor is once switched to ON/OFF in the chargingsub-step, the potential of the pixel electrode lowers by the extent ofΔVp6, as shown by the potential variation of the gate electrode, so thatthe potential difference between the pixel electrode and the opposingelectrode becomes the secondary potential difference of substantiallyzero. While the pixel transistor is in the OFF mode, the potential ofthe source line is set at a potential substantially equal to thepotential of the opposing electrode and is varied in accordance with theON/OFF timing of the pixel transistor in the charging sub-step, likeVsc.

[0195] Subsequently, in the first secondary potential differenceapplication step T₁₂, the pixel transistor is switched ON and OFF at thesame timing as the normal image display period, in each time of whichthe potential of the source line is varied, so that when the pixeltransistor is in the OFF mode, the potential differences between thepotential of the pixel electrode and the potential of the opposingelectrode and between the potential of the pixel electrode and thepotential of the source line become the secondary potential differenceof substantially zero.

[0196] If the potential difference between the potential of the sourceline and the potential of the opposing electrode falls within the rangeof ±1 V when the pixel transistor is in the OFF mode, then there is nodifference in the in-plane transition completion time. This is the sameas the case of the fifth embodiment in which if the potential differencebetween the potential of the pixel electrode and the potential of theopposing electrode falls within ±1 V, then there is presented littleinfluence on the in-plane transition completion time, as mentioned withreference to FIG. 29.

[0197] After the shift from the first secondary potential differenceapplication step T₁₂ to the first primary potential differenceapplication step T₁₁ takes place, the potential of the opposingelectrode is modulated to the first potential, in order to modulate thepotential difference between the pixel electrode and the opposingelectrode to the primary potential difference. Under the influence ofthis, the potential of the pixel electrode is varied only by the extentof ΔVp5 in the direction in which the potential of the opposingelectrode varied, as the potential variation of the opposing electrodeshown at the left side of the period T₁₁ in the diagram. When thepotential of the source line is modulated to be equal to the potentialof the opposing electrode increased by ΔVp6 and then the pixeltransistor is switched to ON/OFF once in the charging sub-step, as isthe case with the first secondary potential difference application stepT₁₂, the potential of the pixel electrode becomes generally equal to thepotential of the opposing electrode in the secondary potentialdifference application step.

[0198] In this primary potential difference application step as well,the potential of the source line is varied at the ON/OFF timing of thepixel transistor. In the primary potential difference application step,the potential differences between the pixel electrode and the opposingelectrode and between the source line and the opposing electrode aresubstantially equal to the potential difference between the potential ofthe opposing electrode in the secondary potential difference applicationstep and the potential of the opposing electrode in the primarypotential difference application step. Consequently, the potential ofthe opposing electrode in each period is so set that the potentialdifference between the potential of the opposing electrode in theprimary potential difference application step and the potential of theopposing electrode in the secondary potential application step can bemodulated to the primary potential difference required for thetransition of the liquid crystal layer.

[0199] When the second secondary potential difference application stepT₂₂ starts, the potential of the opposing electrode varies, under theinfluence of which the potential of the pixel electrode is varied in thedirection in which the potential of the opposing electrode was varied,as illustrated potential variation of the opposing electrode at the leftside of the period T₂₂. The sequent charging operation effected by thepixel transistor causes the potential of the pixel electrode to vary inthe same fashion as in the first secondary potential differenceapplication step, so that the potential of the pixel electrode becomessubstantially equal to the potential of the opposing electrode.

[0200] When the shift from the second secondary potential differenceapplication step T₂₂ to the second primary potential differenceapplication step T₂₁ takes place, the potential of the opposingelectrode varies in the same fashion as in the first primary potentialdifference application step. In this period as well, the primarypotential difference which is the same as that in the first primarypotential difference application step T₁₁ is applied between the pixelelectrode and the opposing electrode by the charging operation of thepixel electrode effected by the pixel transistor.

[0201] Subsequently, in the repeat control step, the secondary potentialdifference application step and the primary potential differenceapplication step are alternately taken until the completion of thetransition of the liquid crystal layer into the bend configuration. Inthe secondary potential difference application step, the potentialdifference between the pixel electrode and the opposing electrode andthe potential difference between the source line and the opposingelectrode become the secondary potential difference of substantiallyzero. In the primary potential difference application step, the primarypotential difference large enough for the transition of the liquidcrystal layer into the bend configuration is applied between the pixelelectrode and the opposing electrode.

[0202] In this example, in addition to the operation mentioned in thefifth embodiment, the potential difference among the pixel electrode,the source line and the opposing electrode, which form a greater part ofthe in-plane area, is modulated to be substantially zero in thesecondary potential difference application step. Consequently, thetransition of the liquid crystal layer into the bend configuration canbe further speeded up than in the fifth embodiment, though there iscomplication to modulate the potential of the source line.

Embodiment 2-7

[0203] Referring to FIGS. 31 and 13, operation of the Embodiment 2-7will be described in which the charge of the pixel electrode effected byON control of the pixel transistor of the fifth embodiment is performedonce at an initial stage of the driving period for effecting thetransition of the liquid crystal layer to the bend configuration.

[0204] Shown in FIG. 31 is the time chart of the potential of the pixelelectrode shown in FIG. 13.

[0205] In FIG. 31, the potential of the opposing electrode is depictedby the thick dotted line; the potential of the gate line is depicted bythe thin dotted line; the potential of the source line is depicted bythe thin solid line; and the potential of the pixel electrode isdepicted by the thick solid line. Vpc at the bottom of the diagramdenotes a potential difference between the pixel electrode and theopposing electrode. Tc denotes the normal image display period. T₁₂denotes the first secondary potential difference application step. T₁₁denotes the first primary potential difference application step. T₂₂denotes the second secondary potential difference application step. T₂₁denotes the second primary potential difference application step.Variation factors of various potentials of the pixel electrode are shownherein.

[0206] In this diagram, when the first secondary potential differenceapplication step T₁₂ starts in the driving period for effecting thetransition of liquid crystal layer to the bend configuration, thepotential of the opposing electrode is modulated to the secondpotential, different from that in the normal image display period. Underthe influence of the potential variation of the opposing electrode, thepotential of the pixel electrode varies only by the extent of ΔVp5 inthe direction in which the potential of the opposing electrode varied,as illustrated in the potential variation of the opposing electrode inthe period T₁₂ shown in the diagram. When the potential of the sourceline is modulated to be equal to the potential of the opposing electrodeincreased by ΔVp6 and then the pixel transistor is once switched toON/OFF, the potential of the pixel electrode lowers only by the extentof ΔVp6, as shown by the potential variation of the gate electrode, sothat it becomes substantially equal to the potential of the opposingelectrode. Subsequently, in the first secondary potential differenceapplication step T₁₂, the potential of the gate line stays unchanged andthe potential difference between the potential of the pixel electrodeand the potential of the opposing electrode 1 remains in the secondarypotential difference of substantially zero.

[0207] After the shift from the first secondary potential differenceapplication step T₁₂ to the first primary potential differenceapplication step T₁₂ takes place, the potential of the opposingelectrode is modulated to the first potential, in order to modulate thepotential difference between the pixel electrode and the opposingelectrode to the primary potential difference. Under the influence ofthis, the potential of the pixel electrode is varied only by the extentof ΔVp5 in the direction in which the potential of the opposingelectrode varied, as the potential variation of the opposing electrodeshown at the left side of the period T₁₂ in the diagram. Even when theshift to the primary potential difference application step takes place,since the charge of the pixel electrode effected by ON control of thepixel transistor is not performed, the potential of the pixel electrodekeeps the potential affected by the potential variation of the opposingelectrode. Thus, the potential of the opposing electrode is set so thatthe potential difference between the pixel electrode and the opposingelectrode can be modulated to the primary potential difference which islarge enough for the transition of the liquid crystal layer to the bendconfiguration to be effected.

[0208] When the second secondary potential difference application stepT₂₂ starts, the potential of the opposing electrode is modulated to thesecond potential. Under the influence of this, the potential of thepixel electrode is varied in the direction in which the potential of theopposing electrode was varied, as illustrated potential variation of theopposing electrode at the shifting part from the period T₁₂ to theperiod T₂₂. The potential of the pixel electrode is then equal to thepotential of the pixel electrode in the potential variation of the gateelectrode in the first secondary potential difference application stepT₁₂, so that the potential difference between the potential of the pixelelectrode and the potential of the opposing electrode becomes thesecondary potential difference of substantially zero.

[0209] When the shift from the second secondary potential differenceapplication step T₂₂ to the second primary potential differenceapplication step T₂₁ takes place, the potential of the opposingelectrode is modulated to the first potential in the same fashion as inthe first primary potential difference application step. In this periodas well, the charge of the pixel electrode is not performed.Consequently, the primary potential difference which is the same as thatin the first primary potential difference application step is appliedbetween the pixel electrode and the opposing electrode.

[0210] Subsequently, in the repeat control step, the secondary potentialdifference application step and the primary potential differenceapplication step are alternately taken until the completion of thetransition of the liquid crystal layer into the bend configuration. Inthe secondary potential difference application step, the potentialdifference between the pixel electrode and the opposing electrodebecomes the secondary potential difference of substantially zero. In theprimary potential difference application step, the primary potentialdifference large enough for the transition of the liquid crystal layerinto the bend configuration is applied between the pixel electrode andthe opposing electrode.

[0211] Although this example involves complication that the ON/OFFtiming of the pixel transistor is varied from that in the normal imagedisplay period, since the number of charges of the pixel electrodeeffected by ON control of the pixel transistor in the secondarypotential difference application step are reduced, as compared with inthe usual timing, the time during which the potential difference betweenthe pixel electrode and the opposing electrode is zero increases in thesecondary potential difference application step. Consequently, thetransition of the liquid crystal layer into the bend configuration canbe further speeded up than in the fifth embodiment.

[0212] It should be noted that if the sufficient charge of the pixelelectrode is not obtained by the first ON control of the pixeltransistor or if the driving period for effecting the transition of theliquid crystal layer to the bend configuration starts asynchronouslywith respect to the normal image display period, so that thenumber-of-times margin is required for the reliable ON control of pixeltransistor, even when the charge of the pixel electrode effected by thefirst ON control of the pixel transistor in the driving period foreffecting the transition of the liquid crystal layer to the bendconfiguration is performed two times or more, rather than one time, thatwould not then have a substantial influence on the effect.

[0213] The first ON control of the pixel transistor is performed withina single field period (16.7 msec. in general) after completion of theswitching to the drive for effecting the transition of the liquidcrystal layer into the bend configuration from the normal image displaytiming.

Embodiment 2-8

[0214] Referring to FIGS. 32 and 13, operation of the eighth embodimentwill be described in which the charge of the pixel electrode effected byON control of the pixel transistor in the charging sub-step of the fifthembodiment is performed once at an initial stage of each of the primarypotential difference application step and the secondary potentialdifference application step within the driving period for effecting thetransition of the liquid crystal layer to the bend configuration.

[0215] Shown in FIG. 32 is the time chart of the potential of the pixelelectrode shown in FIG. 13.

[0216] In this diagram, the potential of the opposing electrode isdepicted by the thick dotted line; the potential of the gate line isdepicted by the thin dotted line; the potential of the source line isdepicted by the thin solid line; and the potential of the pixelelectrode is depicted by the thick solid line. Vpc at the bottom of thediagram denotes a potential difference between the pixel electrode andthe opposing electrode. Tc denotes the normal image display period. T₁₂denotes the first secondary potential difference application step. T₁₁denotes the first primary potential difference application step. T₂₂denotes the second secondary potential difference application step. T₂₁denotes the second primary potential difference application step.Variation factors of various potentials of the pixel electrode are shownherein.

[0217] In FIG. 32, when the first secondary potential differenceapplication step T₁₂ starts in the driving period for effecting thetransition of liquid crystal layer to the bend configuration, thepotential of the opposing electrode is modulated to the secondpotential, different from that in the normal image display period. Underthe influence of the potential variation of the opposing electrode, thepotential of the pixel electrode varies only by the extent of ΔVp5 inthe direction in which the potential of the opposing electrode varied,as illustrated in the potential variation of the opposing electrode inthe period T₁₂ at the left side thereof shown in the diagram. When thepotential of the source line is modulated to be equal to the potentialof the opposing electrode increased by ΔVp6 and then the pixeltransistor is once switched to ON/OFF in the charging sub-step, thepotential of the pixel electrode lowers only by the extent of ΔVp6, asillustrated potential variation of the gate electrode in the period T₁₂at the center thereof, so that it becomes substantially equal to thepotential of the opposing electrode. Subsequently, in the firstsecondary potential difference application step T₁₂, the potential ofthe gate line stays unchanged and the potential difference between thepixel electrode and the opposing electrode remains in the secondarypotential difference of substantially zero.

[0218] After the shift from the first secondary potential differenceapplication step T₁₂ to the first primary potential differenceapplication step T₁₁ takes place, the potential of the opposingelectrode is modulated to the first potential, in order to modulate thepotential difference between the pixel electrode and the opposingelectrode to the primary potential difference. Under the influence ofthis, the potential of the pixel electrode is varied only by the extentof ΔVp5 in the direction in which the potential of the opposingelectrode varied, as the potential variation of the opposing electrodeshown at the left side of the period T₁₁ in the diagram. When thepotential of the source line is modulated to be equal to the potentialof the opposing electrode increased by ΔVp6 and then the pixeltransistor is once switched to ON/OFF in the charge sub-step, as is thecase of the first secondary potential difference application step T₁₂,the potential of the pixel electrode becomes substantially equal to thepotential of the opposing electrode in the secondary potentialdifference application step, as is the case with the potential variationof the gate electrode. Subsequently, in the first primary potentialdifference application step T₁₁, the charge of the pixel electrodeeffected by the ON control of the pixel transistor is not performed, sothat the potential of the pixel electrode stays unchanged.

[0219] Thus, in the primary potential difference applying step, thepotential difference between the pixel electrode and the opposingelectrode is substantially equal to the potential difference between thepotential of the opposing electrode in the secondary potentialdifference application step and the potential of the opposing electrodein the primary potential difference application step. Consequently, thepotential of the opposing electrode in each period is set so that thepotential difference between the potential of the opposing electrode inthe primary potential difference application step and the potential ofthe opposing electrode in the secondary potential difference applicationstep can be modulated to the potential difference required for thetransition of the liquid crystal layer to the bend configuration to beeffected.

[0220] When the second secondary potential difference application stepT₂₂ starts, the potential of the opposing electrode is modulated and,under the influence of this, the potential of the pixel electrode isvaried in the direction in which the potential of the opposing electrodewas varied, as illustrated potential variation of the opposing electrodeat the boundary between the period T₁₂ and the period T₂₂. The potentialof the pixel electrode is then modulated to the potential of the pixelelectrode in the first secondary potential difference application stepthrough the charging operation of the pixel electrode effected by thesequent ON control of the pixel transistor, so that the potentialdifference between the potential of the pixel electrode and thepotential of the opposing electrode becomes the secondary potentialdifference of substantially zero.

[0221] When the shift from the second secondary potential differenceapplication step T₂₂ to the second primary potential differenceapplication step T₂₁ takes place, the potential of the opposingelectrode is modulated in the same fashion as in the first primarypotential difference application step. In this period as well, throughthe initial ON control of the pixel transistor, the primary potentialdifference which is the same as that in the first primary potentialdifference application step is applied between the pixel electrode andthe opposing electrode.

[0222] Subsequently, in the repeat control step, the secondary potentialdifference application step and the primary potential differenceapplication step are alternately taken until the completion of thetransition of the liquid crystal layer into the bend configuration. Inthe secondary potential difference application step, the potentialdifference between the pixel electrode and the opposing electrodebecomes the secondary potential difference of substantially zero. In theprimary potential difference application step, the primary potentialdifference large enough for the transition of the liquid crystal layerinto the bend configuration is applied to the potential differencebetween the pixel electrode and the opposing electrode.

[0223] In this embodiment, since the pixel electrode is charged with thepotential of the source line only once at the initial state of eachperiod, the control of the ON/OFF timing of the pixel transistor isfurther complicated, as compared with that of the seventh embodiment.However, in the secondary potential difference application step, thepixel transistor is put into the ON mode to diminish the time for thepotential difference between the pixel electrode and the opposingelectrode not to vanish, while also the potential of the pixel electrodeis defined at the initial stage of the each period to eliminate theinfluence of the potential variation of the opposing electrode.Consequently, the transition of the liquid crystal layer into the bendconfiguration over the whole area of the panel can be further speeded upthan in the fifth and seventh embodiments.

[0224] As is the case with the seventh embodiment, if the sufficientcharge of the pixel electrode is not obtained by the first ON control ofthe pixel transistor or if the driving period for effecting thetransition of the liquid crystal layer to the bend configuration startsasynchronously with respect to the normal image display period, so thatthe number-of-times margin is required for the reliable ON control ofpixel transistor, even when the charge of the pixel electrode effectedby the ON control of the pixel transistor in the initial stage of eachperiod is performed two times or more, rather than one time, that wouldnot then have a substantial influence on the effect.

Embodiment 2-9

[0225] Referring to FIGS. 33 and 24, operation of the ninth embodimentwill be described in which the OFF voltage of the gate line is convertedinto direct current during the driving period for the transition of theliquid crystal layer of the fifth embodiment to the bend configurationto be effected.

[0226] Shown in FIG. 33 is the time chart of the potential of the pixelelectrode shown in FIG. 24.

[0227] In the diagram, the electrical operation timing of the drivingperiod for effecting the transition of the liquid crystal layer to thebend configuration is the same as that in the fifth embodiment. In theliquid crystal panel with the structure of FIG. 24, the storage capacityCst is formed between the previous gate line 81 and the transparentpixel electrode 21, and the potential of the previous gate line and thepotential of the opposing electrode are modulated in the same direction,in order to apply the potential difference across adjoining columns ofthe picture elements during the normal image display period. Thisoperation is kept all the time when the gate line selects the potentialfor the pixel transistor to be switched OFF, in other words, the OFFvoltage. If this operation is kept in the driving period for thetransition of the liquid crystal layer to the bend configuration, thenthe potential of the pixel electrode is caused to vary by the ΔVp6 ofEq. (6) by the variation of the OFF voltage of the previous gate line,so that the potential difference of some volts is caused, despite of thepotential difference between the pixel electrode and the opposingelectrode being desired to be modulated to the secondary potentialdifference of substantially zero in the secondary potential differenceapplication step, in particular. When the potential difference betweenthe pixel electrode and the opposing electrode exceeds 1 volt in thesecondary potential difference application step, the transitioncompletion time is elongated, as shown in FIG. 29.

[0228] Accordingly, during the driving period for effecting thetransition of the liquid crystal layer to the bend configuration, asshown in FIG. 33, the OFF voltage of the gate line is converted to D.C.(direct current) in the gate line's D.C. converted OFF voltage holdingstep. This can allow the potential variation of the pixel electrode tobe avoided in the secondary potential difference application step, sothat the transition of the liquid crystal layer into the bendconfiguration over the whole area of the panel is speeded up.

Embodiment 2-10

[0229] Referring to FIGS. 34 and 13, operation of the tenth embodimentwill be described.

[0230] Shown in FIG. 34 is the time chart of the potential of the pixelelectrode shown in FIG. 13.

[0231] In the diagram, the potential of the opposing electrode isdepicted by the thick dotted line; the potential of the gate line isdepicted by the thin dotted line; the potential of the source line isdepicted by the thin solid line; and the potential of the pixelelectrode is depicted by the thick solid line. Vpc at the bottom of thediagram denotes a potential difference between the pixel electrode andthe opposing electrode. Vsc denotes a potential difference between thesource line and the opposing electrode. Tc denotes the normal imagedisplay period. T₁₂ denotes the first secondary potential differenceapplication step. T₁₁, denotes the first primary potential differenceapplication step. T₂₂ denotes the second secondary potential differenceapplication step. T₂₁ denotes the second primary potential differenceapplication step. Variation factors of various potentials of the pixelelectrode are shown herein.

[0232] In FIG. 34, when the first secondary potential differenceapplication step T₁₂ starts in the driving period for effecting thetransition of liquid crystal layer to the bend configuration, thepotential of the opposing electrode is modulated to the secondpotential, different from that in the normal image display period. Thepotential 4 of the pixel electrode comes into connection with theopposing electrode through the liquid crystal capacity Clc. At thismoment, the pixel transistor is in the OFF mode and no current issupplied thereto. Accordingly, the potential varies only by the extentof ΔVp5 of the Eq. (5) with respect to the variation of ΔVcom in thepotential of the opposing electrode in the direction in which thepotential of the opposing electrode varied, as illustrated potentialvariation of the opposing electrode at the left side of the period ofT₁₂. When the potential of the source line is modulated to be equal tothe potential of the opposing electrode increased by ΔVp6 and then thepixel transistor is switched to ON/OFF once in the charging sub-step,the potential of the pixel electrode lowers by the extent of ΔVp6, asillustrated potential variation of the gate electrode in the period T₁₂at the center thereof, so that it comes to be substantially equal to thepotential of the opposing electrode.

[0233] After the shift from the first secondary potential differenceapplication step T₁₂ to the first primary potential differenceapplication step T₁₁ takes place, the potential of the opposingelectrode is modulated to the first potential, in order to modulate thepotential difference between the pixel electrode and the opposingelectrode to the primary potential difference. Under the influence ofthis, the potential of the pixel electrode is varied only by the extentof ΔVp5 in the direction in which the potential of the opposingelectrode was varied, as illustrated potential variation of the opposingelectrode at the boundary between the period T₁₁ and the period T₁₂.When the potential of the source line is modulated to be equal to thepotential of the opposing electrode increased by ΔVp6 and then the pixeltransistor is switched to ON/OFF once in the charging sub-step, as isthe case with the first secondary potential difference application stepT₁₂, the potential of the pixel electrode lowers under the influence ofthe potential variation of the potential of the gate line, as is thecase with the potential variation of the gate electrode in the periodT₁₁.

[0234] In the primary potential difference application step, withincreased potential difference between the potential of the pixelelectrode and the opposing electrode, the transition of the liquidcrystal layer to the bend configuration can increasingly be speeded up.Consequently, the potential of the source line is varied in thedirection opposite to the direction in which the potential of theopposing electrode is varied from the secondary potential differenceapplication step to the primary potential difference application step.The potential of the opposing electrode is so set that the potentialdifference between the potential of the opposing electrode and thepotential of the pixel electrode can become the primary potentialdifference required for the transition of the liquid crystal layer tothe bend configuration.

[0235] When the second secondary potential difference application stepT₂₂ starts, the potential of the opposing electrode varies. Under theinfluence of this, the potential of the pixel electrode is varied in thedirection in which the potential of the opposing electrode was varied,as illustrated potential variation of the opposing electrode at theboundary between the period T₁₂ and the period T₂₂. The sequent chargingoperation of the pixel electrode effected by the ON control of the pixeltransistor allows the potential of the pixel electrode to be modulatedto the potential of the pixel electrode in the first secondary potentialdifference application step. As a result of this, the potentialdifference between the potential of the pixel electrode and thepotential of the opposing electrode becomes the secondary potentialdifference of substantially zero.

[0236] When the shift from the second secondary potential differenceapplication step T₂₂ to the second primary potential differenceapplication step T₂₁ takes place, the potential of the opposingelectrode varies in the same fashion as in the first primary potentialdifference application step. In this period as well, the primarypotential difference which is the same as that in the first primarypotential difference application step is applied between the pixelelectrode and the opposing electrode by the charge of the pixelelectrode effected by the ON control of the pixel transistor.

[0237] Subsequently, in the repeat control step, the secondary potentialdifference application step and the primary potential differenceapplication step are alternately taken until the completion of thetransition of the liquid crystal layer into the bend configuration. Inthe secondary potential difference application step, the potentialdifference between the pixel electrode and the opposing electrodebecomes the secondary potential difference of substantially zero, exceptduring the time from the start of the period till the first ON controlof the pixel transistor and during the time during which the pixeltransistor is put into the ON mode to charge the pixel electrode in thecharging sub-step. In the primary potential difference application step,the primary potential difference large enough for the transition of theliquid crystal layer into the bend configuration is applied between thepixel electrode and the opposing electrode, except during the time fromthe start of the period till the first ON control of the pixeltransistor.

[0238] The potential of the source line is varied in the secondarypotential difference application step as well as in the primarypotential difference application step, so that the primary potentialdifference between the pixel electrode and the opposing electrode isincreased in the primary potential difference application step, and assuch can allow the transition of the liquid crystal layer to the bendconfiguration to be speeded up.

[0239] Shown in FIG. 35 is the measurement result of the time requiredfor the completion of the transition which was obtained when the drivingperiod for the transition of the liquid crystal layer to the bendconfiguration to be effected was initiated from the primary potentialdifference application step and from the secondary potential differenceapplication step in the fifth embodiment and the sixth embodiment.

[0240] The primary potential difference between the pixel electrode andthe opposing electrode in the primary potential difference applicationstep is plotted in abscissa. As the potential difference increases, thetransition completion time shortens and, in any level of the potentialdifference, the transition to the bend configuration is completedearlier when the driving period is started from the secondary potentialdifference application step.

Embodiment 2-11

[0241] Referring to FIGS. 36 and 13, operation of the 11th embodimentwill be described.

[0242] In FIG. 36, the potential of the opposing electrode is depictedby the thick dotted line; the potential of the gate line is depicted bythe thin dotted line; the potential of the source line is depicted bythe thin solid line; and the potential of the pixel electrode isdepicted by the thick dotted line. Vpc denotes a potential differencebetween the pixel electrode and the opposing electrode. Three Tcs denotethe normal image display periods, respectively. T₁₂ denotes the firstsecondary potential difference application step. T₁₁ denotes the firstprimary potential difference application step. T₂₂ denotes the secondsecondary potential difference application step. T₂₁ denotes the secondprimary potential difference application step. Variation factors ofvarious potentials of the pixel electrode are shown herein.

[0243] In the diagram, when the first secondary potential differenceapplication step T₁₂ starts in the driving period for effecting thetransition of liquid crystal layer to the bend configuration, thepotential of the opposing electrode is modulated to the secondpotential, different from that in the normal image display period. Thepotential of the pixel electrode comes into connection with the opposingelectrode through the liquid crystal capacity Clc. At this moment, thepixel transistor is in the OFF mode and no current is supplied thereto.Accordingly, the potential varies only by the extent of ΔVp5 withrespect to the variation of ΔVcom in the potential of the opposingelectrode in the direction in which the potential of the opposingelectrode varied, as illustrated at the left side of the period of T₁₂.When the potential of the source line is modulated to be equal to thepotential of the opposing electrode increased by ΔVp6 and then the pixeltransistor is switched to ON/OFF once in the charging sub-step, thepotential of the pixel electrode lowers by the extent of ΔVp6, asillustrated in the center of the period T₁₂, so that it comes to besubstantially equal to the potential of the opposing electrode.

[0244] Subsequently, in the first secondary potential differenceapplication step, the pixel transistor is put into the ON mode in thecharging sub-step, so that the potential difference between thepotential of the pixel electrode and the potential of the opposingelectrode becomes the secondary potential difference of substantiallyzero, except in the process in which the pixel electrode is charged withthe potential of the source line.

[0245] After the shift from the first secondary potential differenceapplication step T₁₂ to the first primary potential differenceapplication step T₁₁ takes place, the potential of the opposingelectrode is modulated to the first potential, in order to modulate thepotential difference between the potential of the pixel electrode andthe potential of the opposing electrode to the primary potentialdifference. Under the influence of this, the potential of the pixelelectrode is varied only by the extent of ΔVp5 in the direction in whichthe potential of the opposing electrode was varied. When the potentialof the source line is modulated to be equal to the potential of theopposing electrode increased by ΔVp6 and then the pixel transistor isswitched to ON/OFF once in the charging sub-step, as is the case withthe first secondary potential difference application step T₁₂, thepotential of the pixel electrode lowers down to the potentialsubstantially equal to the potential of the opposing electrode in thesecondary potential difference application step under the influence ofthe potential variation of the potential of the gate line. In theprimary potential difference application step, the potential of theopposing electrode is so set that the potential difference between thepotential of the pixel electrode and the potential of the opposingelectrode can become the primary potential difference of large enoughfor effecting the transition of the liquid crystal layer to the bendconfiguration. Subsequently, in the first primary potential differenceapplication step T₁₁, the primary potential difference required foreffecting the transition of the liquid crystal layer to the bendconfiguration is applied to the potential difference between thepotential of the pixel electrode and the potential of the opposingelectrode.

[0246] When the second secondary potential difference application stepT₂₂ starts, the potential of the opposing electrode varies, under theinfluence of which the potential of the pixel electrode is varied in thedirection in which the potential of the opposing electrode was varied,as first illustrated potential variation of the opposing electrode inT₂₂. However, when the pixel transistor is switched to ON/OFF once, thepotential difference between the pixel electrode and the opposingelectrode becomes the secondary potential difference of substantiallyzero, except in the process in which the pixel transistor is put in theON mode, so that the pixel electrode is charged with the potential ofthe source line, as is the case of the first secondary potentialdifference application step T₁₂.

[0247] When the shift from the second secondary potential differenceapplication step T₂₂ to the second primary potential differenceapplication step T₂₁ takes place, the potential of the opposingelectrode varies in the same fashion as in the first primary potentialdifference application step. However, not only when the pixel transistoris put in the ON mode and the pixel electrode is charged with thepotential of the source line, but also when the pixel transistor is inthe OFF mode, the primary potential difference required for effectingthe transition of the liquid crystal layer to the bend configuration isapplied to the potential difference between the potential of the pixelelectrode and the potential of the opposing electrode.

[0248] Subsequently, in the repeat control step, the secondary potentialdifference application step and the primary potential differenceapplication step are alternately taken until the completion of thetransition of the liquid crystal layer. In the secondary potentialdifference application step, the potential difference between the pixelelectrode and the opposing electrode becomes the secondary potentialdifference of substantially zero, except during the time from the startof the period till the first ON control of the pixel transistor andduring the time during which the pixel transistor is put into the ONmode. In the primary potential difference application step, the primarypotential difference large enough for the transition of the liquidcrystal into the bend configuration is applied between the pixelelectrode and the opposing electrode, except during the time from thestart of the period till the first ON control of the pixel transistor.

[0249] When image information large in potential difference between thepixel electrode and the opposing electrode is displayed (display ofblack or white, in general) one field in ahigh-potential-difference-for-transition application step at a point oftime when the transition of the liquid crystal layer to the bendconfiguration is nearly completed and prior to the shift to the normalimage display period Tc, enlargement of a bend configuration region ofthe liquid crystal layer is completed, then moving to the next normalimage display period for displaying an intended input image information.

[0250] In general, the primary potential difference application step andthe secondary potential difference application step often takes at leastsome fields, or at least some hundreds of milliseconds in terms of time.When an additional primary potential difference application step or anadditional secondary potential difference application step is taken forthe purpose of completing the transition of the liquid crystal layer tothe bend configuration, the transition completion time increases by somehundreds of milliseconds. There is no need to generate any additionalbend nuclei. For the case that the transition is completed by simplyenlarging the bend region, addition of some tens of milliseconds is justrequired by displaying the image information large in potentialdifference between the pixel electrode and the opposing electrode, andas such can allow the transition completion time to be shortened.

Third Inventive Group

[0251] This inventive group relates to the control of activating therespective parts at power-on.

[0252] In the following, the third inventive group will be describedwith reference to the embodiment.

[0253] Referring to FIGS. 37 and 38, the embodiment of this inventivewill be described below. This inventive group covers one embodiment.

[0254] In FIG. 37, Vg denotes the potential of the gate line. Vs denotesthe potential of the source line. Vp is the potential of the pixelelectrode. Vpc is the potential difference between the pixel electrodeand the opposing electrode. To denotes power-off period. T₁₂ denotes thefirst secondary potential difference application step. T₁₁ denotes thefirst primary potential difference application step. Tc is the normalimage display period. Variation factors of various potentials of thepixel electrode are shown herein.

[0255] In FIG. 38, 3801 denotes a main power supply. 3802 denotes asupply circuit controller, 3803 denotes various power supply voltagegenerating circuits. 3804 denotes a liquid crystal panel controller,3805 denotes a liquid crystal panel. A starting switch 3810 is connectedto the main power supply 3801 and the liquid crystal panel controller3804 from outside. The starting switch 3810 is connected to a counter3811 and in turn to a switching means A 3812 arranged in the interior ofthe liquid crystal panel controller 3804. After the startup, after thepower is supplied to the liquid crystal panel controller 3804, apredetermined time is counted by the counter and, then, picture signalsfrom a normal image signal generating part 3813 are applied to theliquid crystal panel 3805. In the counting of the predetermined time, aswitching means B denoted by 3817 switches between a 1st voltagegenerating means 3814 and a 2nd voltage generating means 3815 in apredetermined period preset by the period counter 3816.

[0256] In the circuit of FIG. 38, the signals input to the liquidcrystal panel are all undefined in the power-off period To. When thepower is turned on by switching on the starting switch 3810, the poweris supplied to the power circuit controller 3802 only, first. Then, thecontroller 3802 controls the various power supply voltage generatingcircuits in order, to initiate the operations of the liquid crystalpanel controller. The circuit constitution having thisliquid-crystal-layer-stably-held activating control step can provide theresult that immediately after power-on, the signals input to the liquidcrystal panel can be converted to the voltage set in the secondarypotential difference application step, so that the period for thetransition of the liquid crystal layer to the bend configuration isinitiated without disarranging the alignment of the liquid crystal layerto which no voltage is applied and, thus, the transition completion timeafter the power-on is shortened.

[0257] When no voltage is applied to the liquid crystal layer, theliquid crystal layer is in the splay configuration, aligning along therubbing groove of the substrate. When some unintended potentialdifference is applied thereto, the transition of the liquid crystalelements is initiated in the order from those liable to transition tothe bend configuration. In the case where the liquid crystal elementsthat remain in the splay configuration and those that are going toinitiate the transition to the bend configuration are randomly mixed inthe in-plane of the liquid crystal panel, even when large potentialdifference is simultaneously applied to those liquid crystal elements,smooth transition to the bend configuration may not be produced. Theembodiment is designed with the aim to prevent generation of the liquidcrystal elements that can initiate the transition to the bendconfiguration when unintended potential difference is applied theretoimmediately after the power-on of the liquid crystal device, therebyallowing the liquid crystal elements that are wholly in the splayconfiguration to initiate the drive for the transition to the bendconfiguration.

[0258] One example of the experimental result obtained by the drivingmode of the embodiment is shown in TABLE 1 below. TABLE 1 State oftransition Plain image display period is presented Driving mode beforeSecond Second period [s] First period [s] of Embodiment period 0.017 1 XX 0.17 1 ▴ X 0.25 1 Δ ▴ 0.33 1 Δ Δ 0.5 1 ◯ Δ 0.75 1 ◯ ◯ 1 1 ◯ ◯

[0259] The driving mode of the embodiment is intended to cover thedriving mode in which the potential of the opposing electrode, thepotential of the gate line and the potential of the source line, whichare inputted to the liquid crystal panel after the power-on, are allallowed to output voltage to be output in the secondary potentialdifference application step. On the other hand, in the conventionaldriving mode in which the normal image display period is presentedbefore the secondary potential difference application step, after thepower-on, the power-supply voltage generating circuits are activatedwithout any restriction and, as a result, the same voltages as those inthe normal image display period are output to the potential of opposingelectrode, the potential of the gate line, and the potential of thesource line, before the secondary potential difference application step.When these two modes were examined for observing the state of transitionat the completion, with varied time required for the secondary potentialdifference application step, it was found that the driving mode of theembodiment could complete the transition in a shorter time.

[0260] In the embodiments of the second inventive group and the thirdinventive group, the potential of the source line need not be modulatedin the same way in the primary potential difference application step andthe secondary potential difference application step. It is permissiblethat the potential of the source line is modulated in different timingand with different potential for each period.

[0261] While the present invention has been described above withreference to the several embodiments, the present invention is notlimited to any of them, of course. Modification may be made in thepresent invention as follows, for example.

[0262] 1) Instead of the liquid crystal display device, a liquid crystalplasma display, an organic EL, and the like are used as the liquidcrystal device;

[0263] 2) A reflective liquid crystal display device or the so-calledROCB, and the like are used as the liquid crystal display device; and

[0264] 3) An optical switch, a light logic device and the like are usedas the liquid crystal device.

INDUSTRIAL APPLICABILITY

[0265] As seen from the description above, according to the presentinvention, the primary potential difference higher than that in thenormal image display period is applied between the pixel electrode andthe opposing electrode which occupy a large space in the liquid crystalpanel, to thereby produce the nucleus for the transition of the liquidcrystal layer to the bend configuration and an enlarged bend region.This enables the transition of the liquid crystal layer to the- bendconfiguration to be caused over the whole area of the panel in a shorttime, to thereby provide a high-response and wide-viewing-angle liquidcrystal panel.

[0266] Also, the primary potential difference application step forapplying the primary potential difference higher than that in the normalimage display period between the pixel electrode and the opposingelectrode of the liquid crystal panel and the secondary potentialdifference application step for applying the secondary potentialdifference smaller than the primary potential difference between themare alternately arranged, to thereby alternately produce the nucleus forthe transition of the liquid crystal layer to the bend configuration andthe enlarged bend region, and the re-alignment of the liquid crystallayer. This enables the transition of the liquid crystal layer to thebend configuration to be caused over the whole area of the panel in ashort time, to thereby provide a high-response and wide-viewing-angleliquid crystal panel.

[0267] Also, the potential of the common electrode forming the storagecapacity between the common electrode and the pixel electrode ismodulated to vary the potential of the pixel electrode so that thepotential difference between the pixel electrode and the opposingelectrode can be made further larger than the potential applied from thesource line, so as to apply the high potential difference to the liquidcrystal layer. This enables the transition of the liquid crystal layerto the bend configuration to be caused over the whole area of the panelin a short time, to thereby provide a high-response andwide-viewing-angle liquid crystal panel.

[0268] Also, the potential of the previous gate line forming the storagecapacity between the precious gate line and the pixel electrode ismodulated to vary the potential of the pixel electrode so that thepotential difference between the pixel electrode and the opposingelectrode can be made further larger than the potential applied from thesource line, so as to apply the high potential difference to the liquidcrystal layer. This enables the transition of the liquid crystal layerto the bend configuration to be caused over the whole area of the panelin a short time, to thereby provide a high-response andwide-viewing-angle liquid crystal panel.

[0269] Also, allowing for some variation in the potential of the sourceline that is caused in the pixel electrode when the pixel transistor isturned off, enables the primary potential difference and the secondarypotential difference effective for the transition of the liquid crystallayer to the bend configuration to be applied between the pixelelectrode and the opposing electrode, without changing the on-off timingof the gate line from that in the normal image display period. This canproduce an accelerated transition of the liquid crystal layer to thebend configuration over the whole area of the panel.

[0270] Also, when the pixel transistor is in the OFF mode, the potentialof the source line is further modulated, with the on-off timing of thegate line kept unchanged from that in the normal image display period,to apply the secondary potential difference effective for the transitionof the liquid crystal layer to the bend configuration between the sourceline and the opposing electrode. This can produce an acceleratedtransition to the bend configuration over the whole area of the panel.

[0271] The charge of the pixel electrode effected by the ON control ofthe pixel transistor is performed at least once at the initial stage ofthe driving period for the transition of the liquid crystal layer to thebend configuration. Although this is cumbersome in that the on-offtiming of the pixel transistor is changed from that in the normal imagedisplay period, since the pixel electrode needs fewer charge in thesecondary potential difference application step than usual, the timeduring which the potential difference between the pixel electrode andthe opposing electrode is zero is increased in the secondary potentialdifference application step. This can produce an accelerated transitionto the bend configuration over the whole area of the panel.

[0272] Also, the charge of the pixel electrode effected by the ONcontrol of the pixel transistor is performed at least once at theinitial stage of each of the primary potential difference applicationstep and the secondary potential difference application step for thetransition of the liquid crystal layer to the bend configuration.Although the control of the on-off timing of the pixel transistor isfurther complicated, since the potential of the pixel electrode isestablished at the initial stage of the each period, the primarypotential difference and the secondary potential difference can beapplied without any influence from the potential variation of theopposing electrode. This can produce an accelerated transition to thebend configuration over the whole area of the panel.

[0273] The OFF voltage of the gate line is converted into direct currentin the driving period for the transition of the liquid crystal layer tothe bend configuration, whereby the pixel electrode is prevented frombeing affected by the potential variation of the gate line particularlyin the secondary potential difference application step. This can producean accelerated transition to the bend configuration over the whole areaof the panel.

[0274] The potential of the source line is varied between the primarypotential difference application step and the secondary potentialdifference application step so that the potential difference between thepixel electrode and the opposing electrode can be further increased inthe primary potential difference application step. This can produce anaccelerated transition to the bend configuration over the whole area ofthe panel.

[0275] Image information large in potential difference between the pixelelectrode and the opposing electrode is displayed one field at a pointof time when the driving period for the transition of the liquid crystallayer to the bend configuration is ended and prior to the shift to thenormal image display period. This can allow the transition to the bendconfiguration to be completed by addition of one field or some tens ofmilliseconds in terms of time, without any addition of the primarypotential difference application step or the secondary potentialdifference application step for the transition to the bend configurationto spend time as more as some hundreds of milliseconds for completion ofthe transition. This can shorten the time for completion of thetransition to the bend configuration over the whole area of the panel.

[0276] The secondary potential difference application step is initiatedwithout disarranging the state of the liquid crystal layer at the timeof power-on to an excessive degree from the state before the power-on.This can bring the liquid crystal layer into alignment in a short time,thus accelerating the transition to the bend configuration over thewhole area of the panel.

[0277] The insulating layer between the gate line electrode and theopposing electrode is reduced in thickness to produce an increasedintensity of electric field between the gate line electrode and theopposing electrode. This can produce an increased number of nuclei forthe transition of the liquid crystal layer to the bend configuration andan accelerated production of nuclei, and as such can produce acceleratedtransition of the liquid crystal layer to the bend configuration overthe whole area of the panel.

[0278] The insulating layer between the gate line electrode and theopposing electrode is reduced in thickness by patterning. This canproduce an increased number of nuclei for the transition of the liquidcrystal layer, to the bend configuration and an accelerated productionof nuclei, and as such can produce accelerated transition to the bendconfiguration over the whole area of the panel.

[0279] The gate line electrode is increased in thickness to produce areduced thickness of the liquid crystal layer on the gate line tothereby produce an increased intensity of the electric field applied tothe liquid crystal layer. This can produce an increased number of nucleifor the transition of the liquid crystal layer to the bend configurationand accelerated production of the nuclei, thus producing acceleratedtransition to the bend configuration over the whole area of the panel.

[0280] The source line forming metal is laminated on the gate lineforming metal in electric contact therewith, to substantially produce anincreased layer thickness of the gate line electrode and a reduced layerthickness of the liquid crystal layer on the gate line. This can producean increased intensity of the electric field applied to the liquidcrystal layer and thus produce accelerated transition to the bendconfiguration.

[0281] The source line forming metal is interposed between the gate lineelectrode and the opposing electrode to provide electric isolationtherebetween, whereby the thickness of the liquid crystal layer on thegate line is reduced. This can produce an increased intensity of theelectric field applied to the liquid crystal layer and thus produceaccelerated transition to the bend configuration.

[0282] The opposing electrode is composed of the first patternedopposing electrode and the second patterned opposing electrode that areelectrically isolated from each other. This enables any selected fieldintensity to be applied to the liquid crystal layer on the gate lineelectrode, while preventing the pixel electrode and the pixel transistorfrom being affected by the voltage variation through the capacitive loadof the liquid crystal layer and the insulating layer. This can producean accelerated transition to the bend configuration. In the normal imagedisplay period, the first opposing electrode and the second opposingelectrode are made to have equal potential, whereby the image qualityexactly identical to that of the conventional liquid crystal displaydevice having the non-patterned opposing electrode can be produced.

[0283] The opposing electrode confronting the gate line isdouble-layered, whereby the thickness of the liquid crystal layer on thegate line is reduced to thereby produce an increased intensity of theelectric field. This can produce accelerated transition to the bendconfiguration.

[0284] The color filter forming resin is laminated on the secondsubstrate at its portion to confront the gate line electrode on thefirst substrate, whereby the opposing electrode on that portion is madeprotuberant to produce a reduced thickness of the liquid crystal layerover the gate line. This can produce an increased electric fieldintensity of the liquid crystal layer and thus produce acceleratedtransition to the bend configuration.

[0285] The pillar-shaped spacer is formed on the second substrate at itsportion to confront the gate line electrode on the first substrate andthe opposing electrode is formed between the pillar-shaped spacer andthe liquid crystal layer, whereby the liquid crystal layer over the gateline is reduced in thickness. This can produce increased electric fieldintensity of the liquid crystal layer and thus produce acceleratedtransition to the bend configuration.

1-44. (Cancelled)
 45. A method for driving a liquid crystal device tocause transition from a splay configuration to a bend configuration of aliquid crystal layer, located between a first substrate on which thinfilm transistors, gate lines, pixel electrodes, and others are locatedin a matrix and a second substrate on which an opposing electrode islocated, the method comprising: applying an electric field between theliquid crystal layer located between the gate line on the firstsubstrate and the opposing electrode on the second substrate, theelectric field being higher than an electric field applied to the liquidcrystal layer in other regions of the liquid crystal device.
 46. Aliquid crystal device to cause transition from a splay configuration toa bend configuration of a liquid crystal layer located between a firstsubstrate on which thin film transistors, pixel electrodes, and gatelines are located in a matrix and a second substrate on which anopposing electrode is located, comprising: means for applying anelectric field between the liquid crystal layer located between the gateline on the first substrate and the opposing electrode on the secondsubstrate, the electric field being higher than an electric fieldapplied to the liquid crystal layer in other regions of liquid crystaldevice.
 47. The liquid crystal device according to claim 46, wherein thegate line on the first substrate is a strong electric field applied gateline which has an insulating layer reduced in thickness at a portionwhere no other metal layer or no semiconductor layer is present betweenthe gate line and the liquid crystal layer.
 48. The liquid crystaldevice according to claim 46, wherein the insulating layer between thegate line on the first substrate and the liquid crystal layer comprisesa high specific inductive capacity insulating layer made of a materialof a specified specific inductive capacity.
 49. The liquid crystaldevice according to claim 46, wherein the gate line on the firstsubstrate is an at-specific-part-thickened gate line which is located tohave an increased metal thickness at a portion where no other metallayer or no semiconductor layer is present between the gate line and theliquid crystal layer.
 50. The liquid crystal device according to claim46, wherein the gate line on the first substrate comprises a partlycontacted gate line in which a source line forming metal is laminated ona gate line forming metal in electric contact therewith at a portionwhere no other metal layer or no semiconductor layer is present betweenthe gate line and the liquid crystal layer.
 51. The liquid crystaldevice according to claim 46, wherein the gate line on the firstsubstrate comprises a partly contacted gate line in which a source lineforming metal is laminated on a gate line forming metal not in electriccontact therewith at a portion where no other metal layer or nosemiconductor layer is present between the gate line and the liquidcrystal layer.
 52. The liquid crystal device according to claim 46,wherein the opposing electrode on the second substrate comprises adivided opposing electrode that is divided into a part confronting thegate line on the first substrate and the remaining part.
 53. The liquidcrystal device according to claim 46, wherein the opposing electrode onthe second substrate comprises an at-confronting-portion thickenedopposing electrode that is located to be larger in thickness at aportion confronting the gate line on the first substrate than at anon-confronting portion.
 54. The liquid crystal device according toclaim 46, wherein the second substrate has a color filter formed ofresin laminated thereon at a portion adjacent the gate line on the firstsubstrate.
 55. The liquid crystal device according to claim 54, whereinthe color filter comprises a color filter comprising a plurality ofdifferent color filters laminated together at peripheries of the colorfilters.
 56. The liquid crystal device according to claim 46, comprisinga pillar-shaped spacer located on the second substrate at a portion ofthe second substrate adjacent the gate line on the first substrate. 57.The liquid crystal device according to claim 56, wherein thepillar-shaped spacer comprises a pillar-shaped spacer means for applyinga potential, which is conductive at least on a liquid crystal layer sidethereof, and for applying a potential equivalent to the gate line to thepillar-shaped spacer at a startup of the liquid crystal device.